Add CI check for clean repo after tests/checks

Should catch forgotten lockfile

.github/workflows/ci.yml

@@ -49,6 +49,17 @@ jobs:
       - name: Tests
         run: cargo llvm-cov nextest --all ${{ matrix.flags }} --lcov --output-path lcov.info
 
+      - name: Check for clean repo
+        shell: bash
+        run: |
+          if [ -n "$(git status --porcelain)" ]; then
+            echo "there are changes";
+            git status --porcelain
+            exit 1
+          else
+            echo "no changes in working directory";
+          fi
+
       - name: Check lockfile
         run: cargo check --locked ${{ matrix.flags }} --all-targets --all