cli: Ensure `ci_support/checkout_merge_commit.sh` is an executable.
cli: Ensure `ci_support/checkout_merge_commit.sh` is an executable.

shadowwalkersb/conda-smithy,shadowwalkersb/conda-smithy,conda-forge/conda-smithy,ocefpaf/conda-smithy,ocefpaf/conda-smithy,conda-forge/conda-smithy