Bump CakeContrib.Guidelines from 1.4.0 to 1.5.1 in /source

Bumps [CakeContrib.Guidelines](https://github.com/cake-contrib/CakeContrib.Guidelines) from 1.4.0 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@1.4.0...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.ExtendedNuGet/Cake.ExtendedNuGet.csproj

@@ -35,7 +35,7 @@
     </PackageReference>
     <PackageReference Include="Cake.Common" Version="3.0.0" PrivateAssets="All" />
     <PackageReference Include="Cake.Core" Version="3.0.0" PrivateAssets="All" />
-    <PackageReference Include="CakeContrib.Guidelines" Version="1.4.0">
+    <PackageReference Include="CakeContrib.Guidelines" Version="1.5.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>