Remove gazelle and its deps from go_rules_dependencies (#1659)

go_rules_dependencies no longer declares the following repositories:

* bazel_gazelle
* com_github_bazelbuild_buildtools
* com_github_pelletier_go_toml

The "gazelle" rule is removed from //go:def.bzl. It has been
deprecated for some time, and "gazelle fix" replaces it.
6 files changed