chore: release 0.13.1

[release-please]

🤖 I have created a release *beep* *boop*

0.13.1 (2020-06-11)

Dependencies

• update dependency com.google.api.grpc:proto-google-common-protos to v1.18.0 (#2) (81a7470)
• update dependency com.google.protobuf:protobuf-bom to v3.12.0 (#6) (73b7a4a)
• update dependency com.google.protobuf:protobuf-bom to v3.12.2 (#8) (5f005b4)
• update dependency io.grpc:grpc-bom to v1.30.0 (#10) (f69ac15)

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