Bump Microsoft.Extensions.Http.Polly from 8.0.7 to 8.0.8 (#350)

Bumps [Microsoft.Extensions.Http.Polly](https://github.com/dotnet/aspnetcore) from 8.0.7 to 8.0.8.
- [Release notes](https://github.com/dotnet/aspnetcore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/main/docs/ReleasePlanning.md)
- [Commits](dotnet/aspnetcore@v8.0.7...v8.0.8)

---
updated-dependencies:
- dependency-name: Microsoft.Extensions.Http.Polly
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Alpaca.Markets.Tests/Alpaca.Markets.Tests.csproj

@@ -13,7 +13,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="8.0.7" />
+    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="8.0.8" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
     <PackageReference Include="Moq" Version="4.20.70" />
     <PackageReference Include="RichardSzalay.MockHttp" Version="7.0.0" />