several small improvements, mostly to make and release

[jhump]

This brings over some recent improvements that were made in the grpcurl repo:

1. Fix all Makefile targets so that make ci does not try to auto-update pinned dependencies to newer versions but instead uses the versions indicated in go.mod.
2. Update to latest grpcurl. Also updates to recent Google API module (work around same build issue for goreleaser as in make release work grpcurl#179).
3. Adds same anonymous imports as used by grpcurl, which adds support for message compression in gRPC calls as well as support for the "xds" URI scheme.

The update to latest grpcurl also ensures that this repo is compatible with the latest grpc-go (which recently deleted a package that was referenced by older grpcurl). See fullstorydev/grpcurl#178 for more details.

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This just in: this also removes Go 1.11 without modules from the Travis CI matrix. When not running in modules mode, CI go gets the latest version of all dependencies. But the latest grpc module no longer supports Go 1.11.

Here's an example red build (which just happened on master): https://travis-ci.com/github/fullstorydev/grpcui/jobs/366918490

[dragonsinth]

Nice. We should copy some of the travis and make stuff -> gosolr I think.