simplify pipeline and allow change of python version dynamically

.github/actions/python_build/action.yml

@@ -19,10 +19,10 @@ description: "Common steps to build the Python environment"
 runs:
   using: "composite"
   steps:
-    - name: Set up Python ${{ matrix.python-version }}
+    - name: Set up Python ${{ PYTHON_VERSION }}
       uses: actions/setup-python@v5
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: ${{ PYTHON_VERSION }}
 
     - name: Install dependencies
       run: |

.github/workflows/ci.yml

@@ -42,12 +42,12 @@ defaults:
   run:
     working-directory: ./
 
+env:
+  PYTHON_VERSION: "3.9"
+
 jobs:
   pylint:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v4
@@ -60,9 +60,6 @@ jobs:
 
   mypy:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v4
@@ -75,9 +72,6 @@ jobs:
 
   black:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v4
@@ -89,17 +83,14 @@ jobs:
 
   pytest:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/python_build
 
       - name: Run pytest with coverage
         run: |
-          coverage run -m pytest --junitxml=./reports/test-results-${{ matrix.python-version }}.xml
+          coverage run -m pytest --junitxml=./reports/test-results-${{ PYTHON_VERSION }}.xml
           coverage xml -o ./reports/coverage.xml
           coverage report -m
 
@@ -108,7 +99,7 @@ jobs:
         uses: MishaKav/pytest-coverage-comment@main
         with:
           pytest-xml-coverage-path: ./reports/coverage.xml
-          junitxml-path: ./reports/test-results-${{ matrix.python-version }}.xml
+          junitxml-path: ./reports/test-results-${{ PYTHON_VERSION }}.xml
 
       - name: Create coverage badge
         uses: schneegans/[email protected]