chore: openssf badge (#105)

Signed-off-by: Skye Gill <[email protected]>

Author: skyerus

README.md

@@ -4,6 +4,7 @@
 [![Go Report Card](https://goreportcard.com/badge/github.com/open-feature/go-sdk)](https://goreportcard.com/report/github.com/open-feature/go-sdk)
 [![codecov](https://codecov.io/gh/open-feature/go-sdk/branch/main/graph/badge.svg?token=FZ17BHNSU5)](https://codecov.io/gh/open-feature/go-sdk)
 [![v0.5.1](https://img.shields.io/static/v1?label=Specification&message=v0.5.1&color=yellow)](https://github.com/open-feature/spec/tree/v0.5.1)
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/6601/badge)](https://bestpractices.coreinfrastructure.org/projects/6601)
 
 This is the Go implementation of [OpenFeature](https://openfeature.dev), a vendor-agnostic abstraction library for evaluating feature flags.