Add snapshot badge to README

Author: StefMa

README.md

@@ -3,6 +3,7 @@
 [![CI](https://github.com/ioki-mobility/SentryProguardGradlePlugin/actions/workflows/test-plugin.yml/badge.svg)](https://github.com/ioki-mobility/SentryProguardGradlePlugin/actions/workflows/test-plugin.yml)
 [![Maven Central](https://img.shields.io/maven-central/v/com.ioki.sentry.proguard/sentry-proguard-gradle-plugin?labelColor=%2324292E&color=%233246c8)](https://central.sonatype.com/namespace/com.ioki.sentry.proguard) <!-- Disabled because of: https://github.com/badges/shields/pull/10997 
 [![Snapshot](https://img.shields.io/nexus/s/com.ioki.sentry.proguard/sentry-proguard-gradle-plugin?labelColor=%2324292E&color=%234f78ff&server=https://s01.oss.sonatype.org)](https://s01.oss.sonatype.org/content/repositories/snapshots/com/ioki/sentry/proguard) -->
+![Snapshot](https://img.shields.io/maven-metadata/v?metadataUrl=https://central.sonatype.com/repository/maven-snapshots/com/ioki/sentry/proguard/sentry-proguard-gradle-plugin/maven-metadata.xml&labelColor=%2324292E&color=%234f78ff&label=maven-snapshot)
 [![MIT](https://img.shields.io/badge/license-MIT-blue.svg?labelColor=%2324292E&color=%23d11064)](https://github.com/ioki-mobility/SentryProguardGradlePlugin/blob/main/LICENSE.md)
 
 A Gradle plugin that generated `UUIDs`, adds it to your `AndroidManifest.xml`