Update Labs.Uwp.Base.props file to use centralized versions

[michael-hawker]

We're not using our centralized versions in the UWP Base Props file here:

https://github.com/CommunityToolkit/Labs-Windows/blob/e6389b00e04160a71e56b409e7fc8cb14ce6fcdf/common/Labs.Uwp.Base.props#L5-L9

From:

https://github.com/CommunityToolkit/Labs-Windows/blob/e6389b00e04160a71e56b409e7fc8cb14ce6fcdf/common/Labs.TargetFrameworks.props#L3

(Also, shouldn't this be Target vs. Min?)

This also appears here:

https://github.com/CommunityToolkit/Labs-Windows/blob/e6389b00e04160a71e56b409e7fc8cb14ce6fcdf/common/Labs.MultiTarget.props#L27-L36

Along with WinUI version, which we may also want to centralize (and also appears in the UWP.base.props.

Nothing urgent, but something to do later. FYI @Arlodotexe in case you have other thoughts here as well.

[Arlodotexe]

(Also, shouldn't this be Target vs. Min?)

I think TargetPlatformVersion would be the target version, and TargetPlatformMinVersion would be the min version.

We can centralize this, but it won't be coming from Labs.TargetFrameworks.props, since the values don't match and that file is only for TargetFrameworks (it gets manipulated via scripts when turning TFMs on and off).

We have "centralized versions" split across a few props files right now: Uno package versions, TargetFrameworks, UWP Target/Min platform versions, even Android target versions are split all over the place.

Maybe instead, we should centralize all of this to a Versions.props file? Something to put all the versioning string values in one place, no side effects for importing.

Edit: The infrastructure that powers Labs can be split up into well defined parts. We'll create "Versions" config files that are appropriate for the infrastructure component that consumes it.

[michael-hawker]

This came up again here where we need slightly different permutations of the numbers for the WinAppSDK assembly attributes here:

CommunityToolkit/Labs-Windows#327 (comment)

They're also in the package.appxmanifest files we have everywhere... not sure how we deal with those.

[Arlodotexe]

They're also in the package.appxmanifest files we have everywhere... not sure how we deal with those.

For the ones where string interpolation won't work, MSBuild String item functions should do the trick

[Arlodotexe]

Given the recent troubles we've had around TFMs, TargetPlatformVersion, TargetPlatformMinVersion and SupportedOSVersion and the age of this ticket, I'd like to keep as-is for now. We've done additional organizing since this ticket was filed, and it seems to be in a good place now.