Docs for SAST ADDITIONAL_CA_CERT_BUNDLE env var

What does this MR do?

Related issues

• Main common MR: gitlab-org/security-products/analyzers/common!76 (merged)
• Refactor common MR: gitlab-org/security-products/analyzers/common!83 (merged)

Less Relevant MRs

These MRs update the version of common and the integration with it.

• gitlab-org/security-products/analyzers/bandit!17 (merged)
• gitlab-org/security-products/analyzers/brakeman!18 (merged)
• gitlab-org/security-products/analyzers/bundler-audit!31 (merged)
• gitlab-org/security-products/analyzers/eslint!17 (merged)
• gitlab-org/security-products/analyzers/flawfinder!15 (merged)
• gitlab-org/security-products/analyzers/gemnasium-maven!33 (merged)
• gitlab-org/security-products/analyzers/gemnasium-python!48 (merged)
• gitlab-org/security-products/analyzers/gemnasium!63 (merged)
• gitlab-org/security-products/analyzers/gosec!28 (merged)
• gitlab-org/security-products/analyzers/klar!30 (merged)
• gitlab-org/security-products/analyzers/kubesec!7 (merged)
• gitlab-org/security-products/analyzers/nodejs-scan!27 (merged)
• gitlab-org/security-products/analyzers/phpcs-security-audit!16 (merged)
• gitlab-org/security-products/analyzers/pmd-apex!9 (merged)
• gitlab-org/security-products/analyzers/retire.js!29 (merged)
• gitlab-org/security-products/analyzers/secrets!30 (merged)
• gitlab-org/security-products/analyzers/security-code-scan!24 (merged)
• gitlab-org/security-products/analyzers/sobelow!14 (merged)
• gitlab-org/security-products/analyzers/spotbugs!28 (merged)
• gitlab-org/security-products/analyzers/tslint!10 (merged)

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
• If applicable, update the permissions table.
• Link docs to and from the higher-level index page, plus other related docs where helpful.
• Apply the documentation label.

Review checklist

All reviewers can help ensure accuracy, clarity, completeness, and adherence to the Documentation Guidelines and Style Guide.

1. Primary Reviewer

• Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.

2. Technical Writer

• Optional: Technical writer review. If not requested for this MR, must be scheduled post-merge. To request for this MR, assign the writer listed for the applicable DevOps stage.

3. Maintainer

1. Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
2. Ensure a release milestone is set.
3. If there has not been a technical writer review, create an issue for one using the Doc Review template.