Update Microsoft.SourceLink.GitHub requirement from 1.1.* to 8.0.*

Updates the requirements on [Microsoft.SourceLink.GitHub](https://github.com/dotnet/sourcelink) to permit the latest version.
- [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
...

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

Author: dependabot[bot]

Directory.Build.props

@@ -36,7 +36,7 @@
     <InheritDocVersion>1.3.*</InheritDocVersion>
     <JetBrainsAnnotationsVersion>2023.3.*</JetBrainsAnnotationsVersion>
     <NpgsqlVersion>7.0.*</NpgsqlVersion>
-    <SourceLinkVersion>1.1.*</SourceLinkVersion>
+    <SourceLinkVersion>8.0.*</SourceLinkVersion>
     <SystemTextJsonVersion>7.0.*</SystemTextJsonVersion>
     <TestSdkVersion>17.8.*</TestSdkVersion>
     <XunitVersion>2.5.*</XunitVersion>