gh-actions: make sure protoc is installed when installing teos

This is a temp fix, the installation usually happens when creating the cache,
so we can remove this after creating a new one

.github/workflows/cln-plugin.yaml

@@ -60,6 +60,7 @@ jobs:
           cd lightning && sudo make install
       - name: Install teos and the plugin
         run: |
+          sudo apt-get update && sudo apt-get install -y protobuf-compiler
           cargo install --locked --path teos 
           cargo install --locked --path watchtower-plugin
       - name: Add test dependencies