Add Service Account Field to Cloud Run

[upodroid]

fixes: #764

Also I can't seem to run make gen/doc , getting the following error

protoc -I=. \
                -I=./vendor/proto/api-common-protos/ \
                --doc_out=./doc --doc_opt=html,index.html \
                ./internal/server/proto/server.proto
google/rpc/status.proto: File not found.
internal/server/proto/server.proto:10:1: Import "google/rpc/status.proto" was not found or had errors.
internal/server/proto/server.proto:403:3: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:502:3: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:687:7: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:694:7: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:583:3: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:945:5: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:952:5: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:1045:5: "google.rpc.Status" is not defined.
internal/server/proto/server.proto:1979:5: "google.rpc.Status" is not defined.
make: *** [gen/doc] Error 1
```

[mitchellh]

This looks good to me. Thank you!

[upodroid]

Thanks