chore: make the PR agnostic of the target branch

Author: averissimo

.github/workflows/build-check-install.yaml

@@ -537,7 +537,6 @@ jobs:
         uses: tj-actions/changed-files@a284dc1814e3fd07f2e34267fc8f81227ed29fb8
         with:
           path: ${{ github.event.repository.name }}/${{ inputs.package-subdirectory }}
-          base_sha: "main"
           files: |
             tests/testthat/*.R
             R/*.R