Bump Microsoft.Extensions.Configuration.EnvironmentVariables

Bumps [Microsoft.Extensions.Configuration.EnvironmentVariables](https://github.com/dotnet/runtime) from 8.0 to 9.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v8.0.0...v9.0.0)

---
updated-dependencies:
- dependency-name: Microsoft.Extensions.Configuration.EnvironmentVariables
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

src/Foundatio.TestHarness/Foundatio.TestHarness.csproj

@@ -8,7 +8,7 @@
     <PackageReference Include="BenchmarkDotNet" Version="0.14.0" />
     <PackageReference Include="Exceptionless.RandomData" Version="1.2.2" />
     <PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" Version="8.10.0" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="8.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="9.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="8.0.1" />
     <PackageReference Include="xunit" Version="2.9.2" />
   </ItemGroup>