change BASE commit for ATS

Given how we will collect the necessary inputs for ATS
(in a periodic workflow in the master branch)
it makes more sense to use commits in the master branch as the BASE
for ATS.

The changes here change the BASE picking to those commits
(i.e. the base of a feature branch)

.github/workflows/codecov_ats.yml

@@ -55,7 +55,7 @@ jobs:
             #                   (i.e. git merge-base ${{ github.sha }}^ origin/main)
             # fetch-depth: 2 - Use if the BASE_COMMIT on codecov_automated_test_selection is at known depth
             #                   (i.e. git rev-parse ${{ github.sha }}^)
-            fetch-depth: 2
+            fetch-depth: 0
         - name: Set up Python 3.10.10
           uses: actions/setup-python@v4
           with:
@@ -98,7 +98,7 @@ jobs:
         - name: Codecov Automated Test Selection
           id: codecov_automated_test_selection
           run: |
-            BASE_COMMIT=$(git rev-parse ${{ github.sha }}^)
+            BASE_COMMIT=$(git merge-base ${{ github.sha }}^ origin/master)
             echo $BASE_COMMIT
             output=$(codecovcli --codecov-yml-path=codecov.yml label-analysis --dry-run --token=${CODECOV_STATIC_TOKEN} --base-sha=${BASE_COMMIT}) || true
             if [ -n "${output}" ];