Fix relative path check

Signed-off-by: Zen <[email protected]>

Author: desultory

src/pycpio/cpio/data.py

@@ -30,7 +30,7 @@ def from_dir(path: Path, parent=None, relative=False, *args, **kwargs):
         if relative is True:
             relative = path
 
-        if relative is not False:
+        if relative:  # If it's not false, none, or an empty string
             relative = Path(relative).resolve()
 
         if relative: