fix: Use maven-releases GAR repository (#67)

The shared 'maven' registry rejected uploads with 403; the correct
target for published releases is 'maven-releases'.

Author: thced

pom.xml

@@ -17,7 +17,7 @@
   <distributionManagement>
     <repository>
       <id>extenda-maven</id>
-      <url>artifactregistry://europe-west1-maven.pkg.dev/extenda/maven</url>
+      <url>artifactregistry://europe-west1-maven.pkg.dev/extenda/maven-releases</url>
     </repository>
   </distributionManagement>