🧪 Add "supported" pip in tox for PR/push @ CI

This is meant to be separate from "latest" and is pinned to the known
working released version of pip. It will run on merges to `main` and
in pull requests. And the cron runs will additionally test the latest
version on PyPI and the `main` branch of the pip repo.

Author: webknjaz

.github/workflows/ci.yml

@@ -63,7 +63,7 @@ jobs:
             fromJSON(
               inputs.cpython-pip-version
               && inputs.cpython-pip-version
-              || '["latest", "lowest"]'
+              || '["supported", "lowest"]'
             )
           }}
     env:
@@ -141,7 +141,7 @@ jobs:
         python-version:
           - pypy-3.8
         pip-version:
-          - latest
+          - supported
     env:
       TOXENV: pip${{ matrix.pip-version }}
     steps:

.github/workflows/cron.yml

@@ -11,4 +11,4 @@ jobs:
     uses: ./.github/workflows/ci.yml
     with:
       cpython-pip-version: >-
-        ["main", "latest", "lowest"]
+        ["main", "latest", "supported", "lowest"]

tox.ini

@@ -1,9 +1,9 @@
 [tox]
 envlist =
     # NOTE: keep this in sync with the env list in .github/workflows/ci.yml.
-    py{38,39,310,311,312,py3}-pip{lowest,latest,main}-coverage
-    pip{lowest,latest,main}-coverage
-    pip{lowest,latest,main}
+    py{38,39,310,311,312,py3}-pip{supported,lowest,latest,main}-coverage
+    pip{supported,lowest,latest,main}-coverage
+    pip{supported,lowest,latest,main}
     checkqa
     readme
 skip_missing_interpreters = True
@@ -14,6 +14,7 @@ extras =
     testing
     coverage: coverage
 deps =
+    pipsupported: pip==24.2
     piplowest: pip==22.2.*
     piplatest: pip
     pipmain: https://github.com/pypa/pip/archive/main.zip