ci: Run coverage tests in parallel (#399)

Instead of re-running the same tests again after the checks have
finished,
run the coverage tests in parallel with the required check.

Also use the latest supported python version for the latter, instead of
running the tests twice with the minimum py version.

.github/workflows/pull-request.yaml

@@ -14,20 +14,19 @@ on:
 env:
   SCCACHE_GHA_ENABLED: "true"
   RUSTC_WRAPPER: "sccache"
+  # A constant location for the uv cache
   UV_CACHE_DIR: /tmp/.uv-cache
 
 
 jobs:
   check:
-    name: Check Python
+    name: Check Python (3.10)
     runs-on: ubuntu-latest
-
-    strategy:
-      matrix:
-        python-version: ['3.10']
+    env:
+      PYTHON_VERSION: '3.10'
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Run sccache-cache
         uses: mozilla-actions/[email protected]
       - name: install-llvm
@@ -38,7 +37,7 @@ jobs:
       - name: "Set up Python"
         uses: actions/setup-python@v5
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: ${{ env.PYTHON_VERSION }}
       - name: Restore uv cache
         uses: actions/cache@v4
         with:
@@ -75,10 +74,12 @@ jobs:
       - name: Minimize uv cache
         run: uv cache prune --ci
 
-  coverage:
-    if: github.event_name != 'merge_group'
-    needs: check
+  test-coverage:
+    name: Check Python (3.12) with coverage
     runs-on: ubuntu-latest
+    env:
+      PYTHON_VERSION: '3.12'
+
     steps:
       - uses: actions/checkout@v4
       - name: Run sccache-cache
@@ -89,7 +90,7 @@ jobs:
       - name: "Set up Python"
         uses: actions/setup-python@v5
         with:
-          python-version: '3.10'
+          python-version: ${{ env.PYTHON_VERSION }}
       - name: Restore uv cache
         uses: actions/cache@v4
         with: