SecurityPolicyDsc: Fix Changelog

[X-Guardian]

Pull Request (PR) description

This PR fixes the changelog by adding square brackets and dates to each of the releases as recommended by Keep a Changelog and required by the ChangeLogManagement module.

This Pull Request (PR) fixes the following issues

None

Task list

• [ ] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [ ] Examples appropriately added/updated.
• [ ] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [ ] New/changed code adheres to DSC Community Style Guidelines.

---

This change is 

[codecov[bot]]

Codecov Report

Merging #149 into master will decrease coverage by 0%. The diff coverage is 84%.

@@          Coverage Diff          @@
##           master   #149   +/-   ##
=====================================
- Coverage      89%    89%   -1%     
=====================================
  Files           5      5           
  Lines         498    573   +75     
=====================================
+ Hits          447    514   +67     
- Misses         51     59    +8