Bump Microsoft.Extensions.Configuration.Abstractions from 3.1.4 to 3.1.8

Bumps [Microsoft.Extensions.Configuration.Abstractions](https://github.com/aspnet/Extensions) from 3.1.4 to 3.1.8.
- [Release notes](https://github.com/aspnet/Extensions/releases)
- [Commits](dotnet/extensions@v3.1.4...v3.1.8)

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

Author: dependabot-preview[bot]

src/examples/AspNetWebApp/AspNetWebApp.csproj

@@ -18,7 +18,7 @@
     <PackageReference Include="Hocon.Extensions.Configuration" Version="2.0.3" />
     <PackageReference Include="Microsoft.AspNetCore.App" />
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="3.1.4" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="3.1.4" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="3.1.8" />
     <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="3.1.4" />
     <PackageReference Include="Microsoft.Extensions.FileProviders.Abstractions" Version="3.1.4" />
     <PackageReference Include="Microsoft.Extensions.FileProviders.Physical" Version="3.1.4" />