Add OpenSSF Scorecard badge to README #32385

Signed-off-by: Yoshiyuki Tabata <[email protected]>

Author: y-tabata

README.md

@@ -2,6 +2,7 @@
 
 ![GitHub Release](https://img.shields.io/github/v/release/keycloak/keycloak?label=latest%20release)
 [![OpenSSF Best Practices](https://bestpractices.coreinfrastructure.org/projects/6818/badge)](https://bestpractices.coreinfrastructure.org/projects/6818)
+[![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/keycloak/keycloak/badge)](https://securityscorecards.dev/viewer/?uri=github.com/keycloak/keycloak)
 [![Artifact Hub](https://img.shields.io/endpoint?url=https://artifacthub.io/badge/repository/keycloak-operator)](https://artifacthub.io/packages/olm/community-operators/keycloak-operator)
 ![GitHub Repo stars](https://img.shields.io/github/stars/keycloak/keycloak?style=flat)
 ![GitHub commit activity](https://img.shields.io/github/commit-activity/m/keycloak/keycloak)