Error if detached head branch is present

Describe the bug

git clone git@github.com:seachicken/can.git
cd can
git checkout 47a4d97
gh poi

Output:

✕ Fetching pull requests...
failed to run external command: git
fatal: ambiguous argument '(HEAD detached at 47a4d97)': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

Your Environment

OS: macOS Monterey
gh (Check with gh --version): 2.6.0
gh-poi (For gh v2.6+ check with gh extension list): 0.4.1

seachicken / gh-poi

Error if detached head branch is present #44