Bump Microsoft.SourceLink.GitHub from 1.1.1 to 8.0.0 (#350)

Bumps [Microsoft.SourceLink.GitHub](https://github.com/dotnet/sourcelink) from 1.1.1 to 8.0.0.
- [Release notes](https://github.com/dotnet/sourcelink/releases)
- [Commits](https://github.com/dotnet/sourcelink/commits)

---
updated-dependencies:
- dependency-name: Microsoft.SourceLink.GitHub
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Directory.Packages.props

@@ -28,6 +28,6 @@
   </ItemGroup>
   <!-- SourceLink support for all Akka.NET projects -->
   <ItemGroup>
-    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="1.1.1" />
+    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
   </ItemGroup>
 </Project>