gRPC-go release 1.7.0

[Menghan Li]

gRPC-go 1.7.0 is now released. Full release notes:

Dependencies

• Remove Go1.6 support (#1492)

API Changes

• Add new Resolver and Balancer APIs (gRFC L9) (#1408)
• New implementation of roundrobin and pickfirst (#1506)

Behavior Changes

• Truncate payload trace string, and turn trace off by default (#1509)

New Features

• Make IO Buffer size configurable. (#1544)
• DNS with new API (#1513)

Performance Improvements

• Use the same hpack encoder on a transport and share it between RPCs. (#1536)

Bug Fixes

• transport: fix racey send to writes channel in WriteStatus (#1546)
• Use Type() method for OAuth tokens instead of accessing TokenType field. (#1537)
• Dedicated goroutine for writing. (#1498)

Documentation

• Update UnknownServiceHandler comment to be clearer about interceptor behavior (#1566)

Please see release at: https://github.com/grpc/grpc-go/releases/tag/v1.7.0