Replaced module CommonResourceHelper with DscResource.Common

[johlju]

Pull Request (PR) description

Added

• Replaced module CommonResourceHelper with the PowerShell Gallery module DscResource.Common v0.2.0.

Changed

• The deploy step is now only run when merged to branch master in the DSC Community upstream repository (not to branch master in a fork which always failed due to missing credentials).

This Pull Request (PR) fixes the following issues

None

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.
• [x] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[johlju]

@PlagueHO Thank you!