CI: Use ubuntu-22.04 to support Python 3.7

Author: amotl

.github/workflows/nightly.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: ['ubuntu-latest']
+        os: ['ubuntu-22.04']
         python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
         cratedb-version: ['nightly']
         sqla-version: ['latest']

.github/workflows/tests.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: ['ubuntu-latest']
+        os: ['ubuntu-22.04']
         python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
         cratedb-version: ['5.5.1']
         sqla-version: ['<1.4', '<1.5', '<2.1']