(maint): Bump CakeContrib.Guidelines from 1.1.1 to 1.5.1 in /Source

Bumps [CakeContrib.Guidelines](https://github.com/cake-contrib/CakeContrib.Guidelines) from 1.1.1 to 1.5.1.
- [Release notes](https://github.com/cake-contrib/CakeContrib.Guidelines/releases)
- [Changelog](https://github.com/cake-contrib/CakeContrib.Guidelines/blob/develop/GitReleaseManager.yaml)
- [Commits](cake-contrib/CakeContrib.Guidelines@1.1.1...1.5.1)

---
updated-dependencies:
- dependency-name: CakeContrib.Guidelines
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Source/Cake.Coveralls/Cake.Coveralls.csproj

@@ -36,7 +36,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="CakeContrib.Guidelines" Version="1.1.1">
+    <PackageReference Include="CakeContrib.Guidelines" Version="1.5.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>