try to use the google protobuf field mask

[butonic]

API changes for cs3org/reva#2001 (comment)

blocked by cs3org/cs3apis-build#14

with the cs3apis-build PR I was able to build the protobuf and go with:

docker run -v /path/to/cs3apis:/root/cs3apis -v /path/to/cs3apis-build/cs3apis-build:/usr/local/bin/cs3apis-build cs3org/cs3apis cs3apis-build -build-proto
docker run -v /path/to/cs3apis:/root/cs3apis -v /path/to/cs3apis-build/cs3apis-build:/usr/local/bin/cs3apis-build cs3org/cs3apis cs3apis-build -build-go

See cs3org/go-cs3apis#44

[butonic]

@ishank011 ci is green, the changes caused by the API change are fully implemented in cs3org/reva#2121

[labkode]

@butonic looks good, let's give it a try

[butonic]

I'll update cs3org/reva#2121 to use the upstream go-cs3org repo