Add protoc installation step to CI workflow

This commit adds a step to the Rust CI workflow for installing the `protoc` compiler. It ensures that the protobuf compiler is available in the CI environment, which is necessary for handling protocol buffers in Rust projects.

.github/workflows/rust.yml

@@ -32,6 +32,12 @@ jobs:
         with:
           just-version: 1.5.0
 
+      - name: Install protoc
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y protobuf-compiler
+          protoc --version
+
       - name: Install Cargo Lambda
         run: |
           pip3 install cargo-lambda