crates workflow: add protoc to workflow environment

Author: daywalker90

.github/workflows/crate-io.yml

@@ -11,6 +11,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
+      - uses: arduino/setup-protoc@v3
       - uses: katyo/publish-crates@v2
         with:
           path: './cln-rpc'