TMP: Switch CI to cov_dep_thermo branch of RMG-Py

Revert this change after the sister PR is merged.

Author: ssun30

.github/workflows/CI.yml

@@ -36,7 +36,7 @@ concurrency:
 
 env:
   # update this to run tests with un merged rmg-py branches
-  RMG_PY_BRANCH: main
+  RMG_PY_BRANCH: 12Chao/cov_dep_therm
 
 jobs:
   build-and-test-linux: