Add ReleaseBranch and MainGitBranch to workflow

[SQLDBAWithABeard]

So that we can create a release I hope

This change adds the ReleaseBranch and MainGitBranch environment variables to the deploy-preview-module workflow. This enhancement ensures that the correct branches are referenced during the deployment process for Pester Help Tests.

Thank you!

Pull Request

Pull Request (PR) description

Task list

• The PR represents a single logical change. i.e. Cosmetic updates should go in different PRs.
• Added an entry under the Unreleased section of in the CHANGELOG.md as per format.
• Local clean build passes without issue or fail tests (build.ps1 -ResolveDependency -Tasks build, test).
• Comment-based help added/updated.
• Examples appropriately added/updated.
• Unit tests added/updated..
• Integration tests added/updated (where possible).
• Documentation added/updated (where applicable).

[github-actions]

Linux Test Results

4 612 tests   4 611 ✅  42s ⏱️
  410 suites      1 💤
    1 files        0 ❌

Results for commit e806c15.

[github-actions]

WinPS51 Test Results

4 612 tests   4 611 ✅  53s ⏱️
  410 suites      1 💤
    1 files        0 ❌

Results for commit e806c15.

[github-actions]

WinPS71 Test Results

4 612 tests   4 611 ✅  52s ⏱️
  410 suites      1 💤
    1 files        0 ❌

Results for commit e806c15.