README.md: Fix broken links and formatting

[X-Guardian]

Pull Request (PR) description

This PR fixes some broken links and formatting in the README.md file.

This Pull Request (PR) fixes the following issues

None

Task list

• [x] Added an entry under the Unreleased section of the change log in the CHANGELOG.md. Entry should say what was changed, and how that affects users (if applicable).
• [x] Documentation added/updated in README.md.
• [ ] Comment-based help added/updated for all new/changed functions.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [ ] Unit tests added/updated.
• [ ] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

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This change is 

[codecov-io]

Codecov Report

Merging #343 into dev will not change coverage. The diff coverage is n/a.

@@         Coverage Diff         @@
##            dev   #343   +/-   ##
===================================
  Coverage    79%    79%           
===================================
  Files        12     12           
  Lines      1768   1768           
  Branches      2      2           
===================================
  Hits       1413   1413           
  Misses      353    353           
  Partials      2      2