Add badge for OpenSSF Best Practices

Author: blowdart

readme.md

@@ -10,6 +10,7 @@ A .NET 8 and .NET 9 library and SDK for [Bluesky](https://bsky.social/) and the
 [![NuGet Version](https://img.shields.io/nuget/vpre/idunno.Bluesky)](https://www.nuget.org/packages/idunno.Bluesky/)
 [![NuGet Downloads](https://img.shields.io/nuget/dt/idunno.Bluesky)](https://www.nuget.org/packages/idunno.Bluesky/)
 [![OpenSSF Scorecard](https://api.scorecard.dev/projects/github.com/blowdart/idunno.Bluesky/badge)](https://scorecard.dev/viewer/?uri=github.com/blowdart/idunno.Bluesky)
+[![OpenSSF Best Practices](https://www.bestpractices.dev/projects/11157/badge)](https://www.bestpractices.dev/projects/11157)
 
 ## Getting Started