Change groupId to com.google.cloud.functions. (#2)

Author: swalkowski

functions-framework-api/pom.xml

@@ -22,7 +22,7 @@
     <version>9</version>
   </parent>
 
-  <groupId>com.google.cloud</groupId>
+  <groupId>com.google.cloud.functions</groupId>
   <artifactId>functions-framework-api</artifactId>
   <version>1.0.0-alpha-1</version>