Bump Microsoft.Bcl.AsyncInterfaces from 6.0.0 to 9.0.9

---
updated-dependencies:
- dependency-name: Microsoft.Bcl.AsyncInterfaces
  dependency-version: 9.0.9
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Ix.NET/Source/refs/System.Linq.Async/System.Linq.Async.csproj

@@ -19,7 +19,7 @@
 
 </PropertyGroup>
   <ItemGroup>
-    <PackageReference Condition="'$(TargetFramework)' == 'net48' or '$(TargetFramework)' == 'netstandard2.0'" Include="Microsoft.Bcl.AsyncInterfaces" Version="6.0.0" />
+    <PackageReference Condition="'$(TargetFramework)' == 'net48' or '$(TargetFramework)' == 'netstandard2.0'" Include="Microsoft.Bcl.AsyncInterfaces" Version="9.0.9" />
 
     <ProjectReference Include="..\..\System.Linq.Async.SourceGenerator\System.Linq.Async.SourceGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" Private="false" />
   </ItemGroup>