Bump prometheus-net from 3.6.0 to 4.0.0

Bumps [prometheus-net](https://github.com/prometheus-net/prometheus-net) from 3.6.0 to 4.0.0.
- [Release notes](https://github.com/prometheus-net/prometheus-net/releases)
- [Changelog](https://github.com/prometheus-net/prometheus-net/blob/master/History)
- [Commits](https://github.com/prometheus-net/prometheus-net/compare/v3.6.0...v4.0.0)

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

OhmGraphite/OhmGraphite.csproj

@@ -31,7 +31,7 @@
     <PackageReference Include="Costura.Fody" Version="3.3.2" />
     <PackageReference Include="NLog.Config" Version="4.7.5" />
     <PackageReference Include="Npgsql" Version="4.1.5" />
-    <PackageReference Include="prometheus-net" Version="3.6.0" />
+    <PackageReference Include="prometheus-net" Version="4.0.0" />
     <PackageReference Include="Resourcer.Fody" Version="1.7.3" />
     <PackageReference Include="TopShelf" Version="4.2.1" />
     <PackageReference Include="Topshelf.NLog" Version="4.2.1" />