Add --change-url with correct value

Create the URL with the change-id rather than the change number.

Change-Id: I7fb753fec0bc776c593062e3e44f48dd9004b085

src/main/java/com/googlesource/gerrit/plugins/hooks/HookArgs.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/hooks/HookArgs.java b/src/main/java/com/googlesource/gerrit/plugins/hooks/HookArgs.java
index fe9bf20..7797e05 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/hooks/HookArgs.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/hooks/HookArgs.java
@@ -73,7 +73,7 @@
     args.add("--change-url");
     String url = urlProvider.get();
     if (change != null && url != null) {
-      args.add(url + change.changeId);
+      args.add(url + change._number);
     } else {
       args.add("");
     }