OZG-6990 extend grpc util: ensure backward compatibility

ozgcloud-common-lib/src/main/java/de/ozgcloud/common/grpc/GrpcUtil.java

@@ -85,6 +85,14 @@ public class GrpcUtil {
 		return Optional.ofNullable(headers.get(key)).map(GrpcUtil::byteToString);
 	}
 
+	/**
+	 * @deprecated since 4.6.0, use {@link #getList(String, Metadata)} instead
+	 */
+	@Deprecated(since = "4.6.0", forRemoval = true)
+	public static List<String> getCollection(String key, Metadata headers) {
+		return getList(key, headers);
+	}
+
 	public static List<String> getList(String key, Metadata headers) {
 		return getList(createKeyOf(key), headers);
 	}