CodeBase for C++ analysis task still points to 16.0

[rainersigwald]

This section of our app.config is stale:

msbuild/src/MSBuild/app.config

Lines 119 to 132 in 8f208e6

	<!-- Workaround for crash in C++ CodeAnalysis scenarios due to https://github.com/Microsoft/msbuild/issues/1675 -->
	<dependentAssembly>
	<assemblyIdentity name="FxCopTask" culture="neutral" publicKeyToken="b03f5f7f11d50a3a" />
	<codeBase version="16.0.0.0" href="..\..\Microsoft\VisualStudio\v16.0\CodeAnalysis\FxCopTask.dll" />
	</dependentAssembly>
	<dependentAssembly>
	<assemblyIdentity name="Microsoft.VisualStudio.CodeAnalysis" culture="neutral" publicKeyToken="b03f5f7f11d50a3a" />
	<codeBase version="16.0.0.0" href="..\..\Microsoft\VisualStudio\v16.0\CodeAnalysis\Microsoft.VisualStudio.CodeAnalysis.dll" />
	</dependentAssembly>
	<dependentAssembly>
	<assemblyIdentity name="Microsoft.VisualStudio.CodeAnalysis.Sdk" culture="neutral" publicKeyToken="b03f5f7f11d50a3a" />
	<codeBase version="16.0.0.0" href="..\..\Microsoft\VisualStudio\v16.0\CodeAnalysis\Microsoft.VisualStudio.CodeAnalysis.Sdk.dll" />
	</dependentAssembly>
	</assemblyBinding>

Those assemblies are now version 17.0 and live in Microsoft\VisualStudio\v17.0\CodeAnalysis.

This was reported by an internal Microsoft partner as blocking upgrade to MSBuild 17.0.

[rainersigwald]

Fixed by #6953.