[Task] Update our top level security policy

[unlikelyzero]

Closes: #4424

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Is this change backwards compatible? For example, developers won't need to change how they are calling the API or how they've extended core plugins such as Tables or Plots.

Author Checklist

• Changes address original issue?
• Unit tests included and/or updated with changes?
• Command line build passes?
• Has this been smoke tested?
• Testing instructions included in associated issue?

[codecov]

Codecov Report

Merging #4429 (7bb99be) into master (6d4a324) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4429   +/-   ##
=======================================
  Coverage   69.76%   69.76%           
=======================================
  Files        1029     1029           
  Lines       36788    36788           
  Branches     1580     1580           
=======================================
  Hits        25664    25664           
  Misses      10729    10729           
  Partials      395      395           

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[akhenry]

I might just be missing something, but it looks to me as though the feature request template has been removed, and a new "maintenance" template has been added, and it seems like we need both?

[akhenry]

This meant to be deleted?

[unlikelyzero]

@akhenry sorry, i wasn't clear in the description. We have an old unused template (from our original attempt at implementing templates). Because it wasn't configured correctly, it's just unused and can be removed.

This PR adds a new maintenance type in addition to remove the improperly formatted one.

[akhenry]

Reviewer Checklist

1. Changes appear to address issue? Y
2. Appropriate unit tests included? N/A
3. Code style and in-line documentation are appropriate? Y
4. Commit messages meet standards? Y
5. Has associated issue been labelled unverified? (only applicable if this PR closes the issue) Y