Pin 18.0 channel for optprof data collection (#12779)

Because of changes between VS 18.0 and 18.3, `main` builds can no longer
collect optprof data for 18.0 builds, so we must pin to the right
channel.

This should fix collection, fixing dotnet/dotnet#3387 (eventually).

Author: rainersigwald

azure-pipelines/.vsts-dotnet-build-jobs.yml

@@ -29,7 +29,7 @@ jobs:
   - name: VisualStudio.MajorVersion
     value: 18
   - name: VisualStudio.ChannelName
-    value: 'int.main'
+    value: 'int.d18.0'
   - name: VisualStudio.DropName
     value: Products/$(System.TeamProject)/$(Build.Repository.Name)/$(Build.SourceBranchName)/$(Build.BuildNumber)
 

eng/Versions.props

@@ -3,7 +3,7 @@
 <Project>
   <Import Project="Version.Details.props" Condition="Exists('Version.Details.props')" />
   <PropertyGroup>
-    <VersionPrefix>18.0.5</VersionPrefix><DotNetFinalVersionKind>release</DotNetFinalVersionKind>
+    <VersionPrefix>18.0.6</VersionPrefix><DotNetFinalVersionKind>release</DotNetFinalVersionKind>
     <PackageValidationBaselineVersion>17.14.8</PackageValidationBaselineVersion>
     <AssemblyVersion>15.1.0.0</AssemblyVersion>
     <PreReleaseVersionLabel>servicing</PreReleaseVersionLabel>