SecurityPolicyDsc: Fix link formatting in README

[DavidKuehn]

Pull Request (PR) description

Fix link formatting in README

This Pull Request (PR) fixes the following issues

Link markdown was incorrectly formatted, resulting in the URL being displayed alongside the link description.

Task list

• [ ] Added an entry under the Unreleased section of the change log in the README.md. Entry should say what was changed, and how that affects users (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 Resource Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Resource Testing Guidelines.
• [ ] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

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This change is 

[codecov-io]

Codecov Report

Merging #120 into master will not change coverage. The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #120   +/-   ##
=====================================
  Coverage      89%    89%           
=====================================
  Files           5      5           
  Lines         493    493           
=====================================
  Hits          443    443           
  Misses         50     50

[jcwalker]

@DavidKuehn thanks for your contribution. Can you have your branch go into the dev branch and not master?

[DavidKuehn]

@jcwalker You are welcome. I think I've changed the branch, but I've never done that before so I'm not sure if I did it properly.