fix: script had bad interpreter path due to changes for linting

[bradegler]

Linting changes introduced in #158 changed the shell on the script from the universally available /bin/sh to /usr/bin/env/bash which does not exist.

This change points the script to /bin/bash which should exist in GHA.

[sethvargo]

Sorry, this should have been #!/usr/bin/env bash (NOT #!/usr/bin/env/bash). That sources bash from the environment instead of relying on a hardcoded path. I probably fat-fingered the wrong one.