fix typo in RuntimeFrameworkVersion under FrameworkReference

[zsd4yr]

MicrosoftNETCoreAppRuntimePackageVersion is used by RuntimeFrameworkVersion under FrameworkReference in Directory.Build.targets as well as global.json's tools.runtimes.dotnet. It is defined in Versions.props below

cli/eng/Versions.props

Lines 21 to 22 in edb2400

	<MicrosoftNETCoreAppRuntimewinx64PackageVersion>5.0.0-alpha1.19520.3</MicrosoftNETCoreAppRuntimewinx64PackageVersion>
	<MicrosoftNETCoreAppRuntimePackageVersion>$(MicrosoftNETCoreAppRuntimewinx64PackageVersion)</MicrosoftNETCoreAppRuntimePackageVersion>

However, it was incorrectly typed in RuntimeFrameworkVersion under FrameworkReference in Directory.Build.targets. This PR fixes that typo

[zsd4yr]

This also appears to be the case on some release branches. including Release/3.0.1xx

cli/Directory.Build.targets

Line 14 in 973a51d

RuntimeFrameworkVersion="$(MicrosoftNETCoreAppRuntimePackageersion)" />

Not sure what if any bugs resulted from this typo so I cannot advise on the scope this change should have

[nguerrera]

Ugh. Thanks

[nguerrera]

The typo is from 19 days ago, after 3.0 shipped. Thankfully. The master branch is closed and has merged into toolset. I'll port this to 3.0/3.1

[zsd4yr]

Thanks @nguerrera --sorry it's hard to keep track of where to make changes nowadays!