docs(orch): add missing go-livepeer dependency (#720)

Author: chrishobcroft

orchestrators/guides/install-go-livepeer.mdx

@@ -162,10 +162,10 @@ Building `livepeer` requires some system dependencies.
 apt-get update && apt-get -y install build-essential pkg-config autoconf git curl yasm
 ```
 
-#### Linux (Ubuntu: 20.04)
+#### Linux (Ubuntu: 20.04 or newer)
 
 ```bash
-apt-get -y install protobuf-compiler-grpc golang-goprotobuf-dev yasm
+apt-get -y install protobuf-compiler-grpc golang-goprotobuf-dev yasm pkg-config
 ```
 
 #### Linux GPU support