Added maven configuration for DocService (#2484)
Added maven configuration for DocService (#2484)

Added `protobuf-maven-plugin` configuration needed to expose services documenation to `DocService`.
anuraaga/armeria,trustin/armeria,kojilin/armeria,line/armeria,minwoox/armeria,trustin/armeria,minwoox/armeria,kojilin/armeria,line/armeria,anuraaga/armeria,anuraaga/armeria,minwoox/armeria,kojilin/armeria,line/armeria,minwoox/armeria,minwoox/armeria,anuraaga/armeria,line/armeria,anuraaga/armeria,kojilin/armeria,trustin/armeria,kojilin/armeria,anuraaga/armeria,line/armeria,trustin/armeria,trustin/armeria,trustin/armeria,minwoox/armeria,line/armeria,kojilin/armeria