tweak workflow trigger again.

Author: ilaflott

.github/workflows/create_test_conda_env.yml

@@ -1,7 +1,11 @@
 name: create_test_conda_env
 
+on:
 on:
   push:
+    branches:
+      - main        # can comment this out for a fork branch to run on push, if needed
+  pull_request:     # run for any PR targeting any branch
 
 # cancel running jobs if theres a newer push
 concurrency: