Bump Microsoft.Extensions.Configuration.EnvironmentVariables

Bumps [Microsoft.Extensions.Configuration.EnvironmentVariables](https://github.com/dotnet/runtime) from 6.0.1 to 8.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v6.0.1...v8.0.0)

---
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]>

Directory.Build.props

@@ -39,7 +39,7 @@
       <XunitCombinatorialVersion>1.5.25</XunitCombinatorialVersion>
       <MicrosoftExtensionsConfigurationVersion>6.0.1</MicrosoftExtensionsConfigurationVersion>
       <MicrosoftExtensionsConfigurationBinderVersion>6.0.0</MicrosoftExtensionsConfigurationBinderVersion>
-      <MicrosoftExtensionsConfigurationEnvironmentVariablesVersion>6.0.1</MicrosoftExtensionsConfigurationEnvironmentVariablesVersion>
+      <MicrosoftExtensionsConfigurationEnvironmentVariablesVersion>8.0.0</MicrosoftExtensionsConfigurationEnvironmentVariablesVersion>
       <MicrosoftExtensionsConfigurationJsonVersion>6.0.0</MicrosoftExtensionsConfigurationJsonVersion>
       <SystemIOPortsVersion>6.0.0</SystemIOPortsVersion>
       <XUnitRunnerVisualStudio>2.4.5</XUnitRunnerVisualStudio>