DEBUG=true in env results in error

[stuertz]

I have an environment with DEBUG set to "true", this leads to an error:

Can be reproduced with:

> DEBUG=true pre-commit run shell-lint
Shell Syntax Check.......................................................Failed
- hook id: shell-lint
- exit code: 1
[...]/pre_commit_hooks/shell-lint.sh: line 8: true: unbound variable

[stuertz]

could you force a new version for this?

[RadxaYuntian]

New release will be appreciated.