Respect default shell choice

[ChrisThrasher]

Describe the bug
I use

defaults:
  run:
    shell: bash

at the top of my shell scripts to ensure all steps of all jobs use bash. One such step is using this retry actions yet the shell used to run commands inside this action does not automatically use Bash.

Expected behavior
The default shell is detected, if set, and is used.

Logs
Here is a failing CI pipeline caused by removing shell: bash.