Bump Microsoft.SourceLink.GitHub from 1.1.1 to 8.0.0 (#294)

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

@@ -34,6 +34,6 @@
     </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>