chore(lint): bump golangci lint config to v2, address lint findings

[mattsre]

Bumps the golangci-lint config to v2, address some lint findings from new config. Config was migrated with automation - https://golangci-lint.run/docs/product/migration-guide/

Motivation

New versions of golangci-lint don't support the old v1 config file format. Maintaining two versions of golangci-lint locally can be annoying, especially when you are integrating golangci-lint into your editor for lsp 😄

Modifications

• Add some local dev tools to gitignore
• migrate the golangci-lint config file to v2 format

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Documentation

• no-need-doc

Only upgrading tooling separate from the operator itself