wait for unity processes to die

ci/build.sh

@@ -7,11 +7,12 @@ editorlogpath="$HOME/Library/Logs/Unity/Editor.log"
 editorpath="/Applications/Unity/Hub/Editor/$unityversion/Unity.app"
 
 # find and kill existing unity instances
-if pgrep -x Unity
-then
 echo "terminating existing unity processes..."
+while pgrep -x Unity > /dev/null
+do
     kill $(pgrep Unity)
-fi
+    sleep 1
+done
 
 # remove previous Editor.log
 echo "removing previous editor log..."