CI: Run pre-release tests only on SPEC-0 supported Python

Author: effigies

.github/workflows/test.yml

@@ -152,6 +152,11 @@ jobs:
           # Drop pre tests for macos-13
           - os: macos-13
             dependencies: pre
+          # Drop pre tests for SPEC-0-unsupported Python versions
+          - python-version: '3.8'
+            dependencies: pre
+          - python-version: '3.9'
+            dependencies: pre
 
     env:
       DEPENDS: ${{ matrix.dependencies }}