fix ci: add missing protobuf (#493)

https://github.com/paritytech/zombienet-sdk/actions/runs/20819619711/job/59804239266

Author: mchristou

.github/workflows/release.yml

@@ -26,6 +26,17 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
+      - name: Install protoc on Ubuntu
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y protobuf-compiler
+
+      - name: Install protoc on macOS
+        if: matrix.os == 'macos-latest'
+        run: |
+          brew install protobuf
+
       - name: Build release binary
         run: cargo build --release --bin zombie-cli --target ${{ matrix.target }}