ADKDSKey: Fixes #648, the resource did not work due to a non-working date conversion

[raandree]

Pull Request (PR) description

The resource did not work due to a non-working date conversion as described in #648.

This Pull Request (PR) fixes the following issues

• Fixes #648

Task list

• [x] 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.

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This change is 

[codecov[bot]]

Codecov Report

Merging #649 (bfddebb) into main (04f5f39) will not change coverage. The diff coverage is 100%.

@@         Coverage Diff         @@
##           main   #649   +/-   ##
===================================
  Coverage    98%    98%           
===================================
  Files        25     25           
  Lines      3408   3408           
===================================
  Hits       3340   3340           
  Misses       68     68           

Impacted Files	Coverage Δ
...urce/DSCResources/MSFT_ADKDSKey/MSFT_ADKDSKey.psm1	100% <100%> (ø)

[johlju]

Let us merge this based on the https://github.com/dsccommunity/ActiveDirectoryDsc/issues/648#issuecomment-850886442.