Bump actions/checkout from 5 to 6 (#478)

* Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

* also apply to example workflows

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tyler Yankee <[email protected]>

Author: dependabot[bot]

.github/workflows/bazel_download.yml

@@ -12,7 +12,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_bazel_download
         run: |

.github/workflows/ci.yml

@@ -49,7 +49,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         uses: actions/setup-python@v6
         with:

.github/workflows/cmake_installed.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: macos-15
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # See issue https://github.com/actions/setup-python/issues/577.  There is
       # some kind of environment conflict between the symlinks found in the
       # GitHub Actions runner and `brew upgrade python` where `brew` detects and
@@ -42,7 +42,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_cmake_installed
         run: |

.github/workflows/cmake_installed_apt.yml

@@ -12,7 +12,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_cmake_installed_apt
         run: |

.github/workflows/pip.yml

@@ -13,7 +13,7 @@ jobs:
       PYTHON_VERSION: '3.14'
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # See issue https://github.com/actions/setup-python/issues/577.  There is
       # some kind of environment conflict between the symlinks found in the
       # GitHub Actions runner and `brew upgrade python` where `brew` detects and
@@ -48,7 +48,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: pip setup
         working-directory: drake_pip
         run: |

.github/workflows/poetry.yml

@@ -13,7 +13,7 @@ jobs:
       PYTHON_VERSION: '3.14'
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # See issue https://github.com/actions/setup-python/issues/577.  There is
       # some kind of environment conflict between the symlinks found in the
       # GitHub Actions runner and `brew upgrade python` where `brew` detects and
@@ -49,7 +49,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # setup and test must occur in one step
       # because when poetry is installed, the update to PATH
       # does not persist between steps on GHA

drake_bazel_download/.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_bazel_download
         run: |

drake_cmake_installed/.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
     runs-on: macos-15
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # See issue https://github.com/actions/setup-python/issues/577.  There is
       # some kind of environment conflict between the symlinks found in the
       # GitHub Actions runner and `brew upgrade python` where `brew` detects and
@@ -61,7 +61,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_cmake_installed
         run: |

drake_cmake_installed_apt/.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: setup
         working-directory: drake_cmake_installed_apt
         run: |

drake_pip/.github/workflows/ci.yml

@@ -32,7 +32,7 @@ jobs:
       PYTHON_VERSION: '3.14'
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       # See issue https://github.com/actions/setup-python/issues/577.  There is
       # some kind of environment conflict between the symlinks found in the
       # GitHub Actions runner and `brew upgrade python` where `brew` detects and
@@ -67,7 +67,7 @@ jobs:
     container: ubuntu:noble
     steps:
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: pip setup
         working-directory: drake_pip
         run: |