BUG: LGTM is going away

[wenottingham]

Describe the bug
The SAST check states in its docs (and in the code) that it checks for CodeQL (github-code-scanning), LGTM and SonarCloud in the recent (~30) merged PRs, or the use of "github/codeql-action" in a GitHub workflow.

LGTM is being shut down at the end of December, and is no longer accepting new signups. See https://github.blog/2022-08-15-the-next-step-for-lgtm-com-github-code-scanning/ for details.

The checks can probably still check for LGTM, but the docs should probably clarify that it's not something new users should try.

Reproduction steps
Steps to reproduce the behavior:

1. Look at SAST check docs
2. Open up the list of services

Expected behavior
All active services used, no deprecated or being-shut-down services suggested.

Additional context

[naveensrinivasan]

@wenottingham Thank you! Would you be interested in doing a PR for this?