Fix GitHub Actions runner and Python matrix

Author: willronchetti

.github/workflows/main.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        python_version: [3.9, 3.11, 3.12]
+        python_version: [3.11, 3.12]
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
@@ -62,7 +62,7 @@ jobs:
       - name: Coveralls
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        if: ${{ matrix.python_version == '3.9' }}
+        if: ${{ matrix.python_version == '3.11' }}
         run: |
           pip install coveralls
           poetry run coveralls --service=github

.github/workflows/static-checks.yml

@@ -19,7 +19,7 @@ jobs:
   build:
     name: Static checks of source code (PEP8 and our custom checks)
     # The type of runner that the job will run on
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps: