chore: add badges to readmne

Signed-off-by: Jendrik Johannes <[email protected]>

README.md

@@ -1,3 +1,7 @@
+[![Build Status](https://img.shields.io/endpoint.svg?url=https%3A%2F%2Factions-badge.atrox.dev%2Fhiero-ledger%2Fhiero-gradle-conventions%2Fbadge%3Fref%3Dmain&style=flat)](https://actions-badge.atrox.dev/hiero-ledger/hiero-gradle-conventions/goto?ref=main)
+[![Gradle Plugin Portal](https://img.shields.io/maven-metadata/v?label=Plugin%20Portal&metadataUrl=https%3A%2F%2Fplugins.gradle.org%2Fm2%2Forg%2Fhiero%2Fgradle%2Fhiero-gradle-conventions%2Fmaven-metadata.xml)](https://plugins.gradle.org/plugin/org.hiero.gradle.build)
+[![License](https://img.shields.io/badge/license-apache2-blue.svg)](LICENSE)
+
 # Hiero Gradle Conventions
 
 Gradle [convention plugins](https://docs.gradle.org/current/samples/sample_convention_plugins.html) used by Hiero projects.