Updates pom with variable for GitHub Packages

- GITHUB_REPOSITORY is predefined by GitHub
- Enables SNAPSHOT release workflow to also work for forks

Author: FrankSchnicke

pom.xml

@@ -251,7 +251,7 @@
       <repository>
         <id>github</id>
         <name>GitHub Apache Maven Packages</name>
-        <url>https://maven.pkg.github.com/admin-shell-io/java-serializer</url>
+        <url>https://maven.pkg.github.com/${env.GITHUB_REPOSITORY}</url>
       </repository>
     </distributionManagement>