.github: fix error when making checks for CoCo guest pull

Fix error when making checks:
```
error: failed to run custom build command for `image-rs v0.1.0
(https://github.com/confidential-containers/guest-components?tag=v0.8.0#e849dc89)`

Caused by:
  process didn't exit successfully: `/home/runner/work/kata-containers/kata-containers/src/
  agent/target/release/build/image-rs-fd932206d09362b7/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-changed=./protos/getresource.proto
  cargo:rerun-if-changed=./protos

  --- stderr
  thread 'main' panicked at 'Could not find `protoc` installation and this build crate cannot proceed without
  this knowledge. If `protoc` is installed and this crate had trouble finding
  it, you can set the `PROTOC` environment variable with the specific path to your
  installed `protoc` binary.If you're on debian, try `apt-get install protobuf-compiler`
  or download it from https://github.com/protocolbuffers/protobuf/releases
```

Fixes #8673

Signed-off-by: ChengyuZhu6 <chengyu.zhu@intel.com>

.github/workflows/static-checks.yaml

@@ -107,6 +107,9 @@ jobs:
           echo "Set environment variables for the libseccomp crate to link the libseccomp library statically"
           echo "LIBSECCOMP_LINK_TYPE=static" >> $GITHUB_ENV
           echo "LIBSECCOMP_LIB_PATH=${libseccomp_install_dir}/lib" >> $GITHUB_ENV
+      - name: Install protobuf-compiler
+        if: ${{ matrix.command == 'make check' && matrix.component == 'agent' }}
+        run: sudo apt-get -y install protobuf-compiler
       - name: Setup XDG_RUNTIME_DIR for the `runtime` tests
         if: ${{ matrix.command != 'make vendor' && matrix.command != 'make check' && matrix.component == 'runtime' }}
         run: |