Update versioning strategy

[jeromelaban]

PR Type

What kind of change does this PR introduce?

• Build or CI related changes

What is the new behavior?

Document the GitVersion-base release strategy, and move to mainline mode for release/stable branches. Tagging is now required as documented.

PR Checklist

Please check if your PR fulfills the following requirements:

• [ ] Tested code with current supported SDKs
• [x] Docs have been added/updated which fit documentation template. (for bug fixes / features)
• [ ] Tests for the changes have been added (for bug fixes / features) (if applicable)
• [ ] Contains NO breaking changes
• [ ] Updated the Release Notes
• [ ] Associated with an issue (GitHub or internal)

Other information

Internal Issue (If applicable):

[dr1rrb]

We should clear all the old tags before starting to use this procedure (Or at least all tags that are not properly formated):

C:\Src\GitHub\unoplatform\Uno>git tag --list
1-41
1-42
1-43-0-dev-657
1-43-1
1-44-1
1-45-0
1.29-wasm
1.30.1-wasm
1.40
__BEFORE_REBASE_NETSTD-WASM
hr-pre1
v7.47.0

[jeromelaban]

@dr1rrb that's for Uno :) We'll do that there as well.