Updates to SECURITY.md

[brooke-hamilton]

Description

Updated SECURITY.md to fix linting issues and ensure all text is correct and applies to this project. All text is boilerplate applied by MSFT policy and did not require any changes.

Note: There is a comment tag at the beginning and end of the file which I believe should stay in order to satisfy automated checks.

Issue reference

The issue this PR will close: #22

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles or validates correctly
• BASH scripts have been validated using shellcheck
• All tests pass (manual and automated)
• The documentation is updated to cover any new or changed features
• Markdown files have been linted using the recommended linter. (See .vscode/extensions.json.)
• Relevant issues are linked to this PR