build(deps): bump Microsoft.Extensions.Configuration.EnvironmentVariables

Bumps [Microsoft.Extensions.Configuration.EnvironmentVariables](https://github.com/dotnet/runtime) from 7.0.0 to 8.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v7.0.0...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]>

Author: dependabot[bot]

test/Pomelo.Extensions.Caching.MySql.Tests/Pomelo.Extensions.Caching.MySql.Tests.csproj

@@ -30,7 +30,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-		<PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="7.0.0" />
+		<PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="8.0.0" />
 		<PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="7.0.0" />
 		<PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="7.0.0" />
 		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />