Use pull_request_target in add_to_project.

Need to use pull_request_target to enable PRs access to Org secrets. See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target

Author: jrhemstad

.github/workflows/add_to_project.yml

@@ -5,7 +5,7 @@ on:
     types:
       - opened
 
-  pull_request:
+  pull_request_target:
     types:
       - opened