Update gitignore to ignore config files that we don't want interfering with builds

asdf tool version config files are included in git and should not be.

The .tool-versions file is causing problems for users who have go installed via asdf.

What is happening:

• make lint command is called inside gitlab-runner
• goargs is pulled in
• a custom linting analyzer is generated using the version of go that is set in .tool-versions in the goargs repo
• the current version of golang in the terminal, set by asdf, will attempt to use the goargs analyzer
• if the terminal's go version does not match the goargs go version, the following error will happen:

ERRO Unable to load custom analyzer goargs:.tmp/goargs.so, plugin.Open("/Users/davisbickford/workspace/gitlab/runner-repos-for-testing-lint/gitlab-runner/.tmp/goargs"): plugin was built with a different version of package runtime
ERRO Running error: unknown linters: 'goargs', run 'golangci-lint help linters' to see the list of supported linters
make: *** [lint] Error 3

QA Steps (need a couple QA people, someone with asdf golang install and someone without)

MR in gitlab-runner pointing to this branch - static analysis job succeeds

• manual consumption test, MR pointing to this branch, job succeeds

Person with asdf golang install

• On a computer with golang installed via asdf
• terminal into the gitlab-runner repo
• run asdf local golang 1.18.7 ; rm .tmp/goargs.so ; make clean ; make lint
• confirm you get the error up above regarding the custom analyzer
• within the gitlab-runner repo, update this line in Makefile to clone this branch instead:
  • git clone --branch dbickford-remove-asdf-config https://gitlab.com/gitlab-org/language-tools/go/linters/goargs.git --no-tags --depth 1 $(TOOL_BUILD_DIR)
• back in the terminal, run rm .tmp/goargs.so ; make clean ; make lint
• this time, no error. Bonus points if you put put a linting issue in a file to confirm output works.

Person with NON-asdf golang install

• within the gitlab-runner repo, update this line in Makefile to clone this branch instead:
  • `git clone --branch dbickford-remove-asdf-config https://gitlab.com/gitlab-org/language-tools/go/linters/goargs.git --no-tags --depth 1
• terminal into the gitlab-runner repo
• run rm .tmp/goargs.so ; make clean ; make lint
• confirm linting is working (no errors)