Bazel incompatible changes

[laurentlb]

It seems like the repository doesn't build with Bazel incompatible changes.
With --incompatible_disallow_old_style_args_add, we get:

	File "/usr/local/google/home/laurentlb/.cache/bazel/_bazel_laurentlb/59217ff323cdbf9f3c98b0d19e37510b/external/grpc_ecosystem_grpc_gateway/protoc-gen-swagger/defs.bzl", line 73, in depset
		_run_proto_gen_swagger(ctx, direct_proto_srcs = proto.dir..., <5 more arguments>)
	File "/usr/local/google/home/laurentlb/.cache/bazel/_bazel_laurentlb/59217ff323cdbf9f3c98b0d19e37510b/external/grpc_ecosystem_grpc_gateway/protoc-gen-swagger/defs.bzl", line 53, in _run_proto_gen_swagger
		args.add([("-I%s" % include) for include ...])
Args#add no longer accepts vectorized arguments when --incompatible_disallow_old_style_args_add is set. Please use Args#add_all or Args#add_joined.

One way to check whether it's compatible, and find the future breakages, is to use bazelisk, e.g.
bazelisk --migrate test //...

(cc @ensonic because https://github.com/googlecloudrobotics/core depends on this)

[johanbrandhorst]

Thanks for reporting this. I'll just CC some people that know better than I.

CC @drigz @achew22

[achew22]

bazelbuild/bazel-integration-testing#108 needs to be merged then we can switch to it and it'll fix it.

@laurentlb thanks so much for doing this 😄