Simplify build_lint.yml

.github/workflows/build_lint.yml

@@ -22,17 +22,13 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ${{ matrix.os }}-latest
-    strategy:
-      matrix:
-        os: [ubuntu]
-        python-version: ["3.12"]
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - name: Set up Python ${{ matrix.python-version }}
+    - name: Set up Python
       uses: actions/setup-python@v5
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: "3.12"
     - name: Install dependencies
       run: pip install mesa pytest
     - name: Test with pytest