ci: check if Cargo.lock is up-to-date

Author: weihanglo

.github/workflows/main.yml

@@ -97,6 +97,8 @@ jobs:
       run: echo CARGO_CONTAINER_TESTS=1 >> $GITHUB_ENV
       if: matrix.os == 'ubuntu-latest'
 
+    - name: Check if Cargo.lock is up-to-date
+      run: cargo fetch --locked
     - run: cargo test -p cargo
     - name: Clear intermediate test output
       run: ci/clean-test-output.sh