chore: set reg test branch

Author: tstephen-nhs

.github/workflows/run_regression_tests.yml

@@ -65,7 +65,7 @@ jobs:
         run: |
           if [[ "$TARGET_ENVIRONMENT" != "prod" && "$TARGET_ENVIRONMENT" != "ref" ]]; then
             # this should be the tag of the tests you want to run
-            REGRESSION_TEST_REPO_TAG=v3.10.9
+            REGRESSION_TEST_REPO_TAG=aea-6055-gsul-boto-lambda-invoke
 
             # this should be the tag of the regression test workflow you want to run
             # This will normally be the same as REGRESSION_TEST_REPO_TAG