Get branch name from head instead of base

Not the name of the branch were the changes should pulled into is
needed. The name of the current branch must be determined.

Signed-off-by: Tim Krüger <t@timkrueger.me>

scripts/analysis/getBranchName.sh

@@ -7,5 +7,5 @@
 if [ -z "$3" ] ; then
     git branch | grep '\*' | cut -d' ' -f2
 else
-    curl 2>/dev/null -u "$1":"$2" "https://api.github.com/repos/nextcloud/talk-android/pulls/$3" | jq .base.ref
+    curl 2>/dev/null -u "$1":"$2" "https://api.github.com/repos/nextcloud/talk-android/pulls/$3" | jq .head.ref
 fi