ci: check if crate can be packaged

Author: phip1611

.github/workflows/release.yml

@@ -14,6 +14,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - name: Check cargo package
+        # Checks if `cargo package` can run successfully. This saves us from
+        # situations where this is only noticed after a merge and releases
+        # were made only partially.
+        run: cargo package
       - run: |
           cargo install auto-release
           auto-release --condition body -p uefi-raw -p uefi-macros -p uefi