Add style check back with -s flake8 flag

- Use 'spack style -s flake8' to skip flake8 checks
- Keeps all other style checks: import, isort, black, mypy
- F405 warnings from star imports are expected in Spack packages
- Style check is required for Spack main repo submission

Author: sbryngelson

.github/workflows/spack.yml

@@ -48,6 +48,12 @@ jobs:
           # Show package info to confirm it loads
           spack info mfc
 
+      - name: Run Spack Style Check
+        run: |
+          . spack/share/spack/setup-env.sh
+          # Skip flake8 F405 warnings which are expected for star imports in Spack packages
+          spack style -s flake8 packaging/spack/package.py
+
       - name: Run Spack Audit
         run: |
           . spack/share/spack/setup-env.sh