Fix: Fix detecting poetry mode in existing installations

Ensure that old shebang line works with poery mode. With new setups
`/usr/bin/env -S poetry run python` is used instead of `/usr/bin/env -S
poetry run python3` for the poetry shebang line. The old line must be
still detected as poetry mode.

autohooks/hooks.py

@@ -72,7 +72,7 @@ def read_mode(self) -> Mode:
 
         if shebang == PYTHON3_SHEBANG:
             return Mode.PYTHONPATH
-        if shebang == POETRY_SHEBANG:
+        if shebang.startswith(POETRY_SHEBANG):
             return Mode.POETRY
         if shebang == PIPENV_SHEBANG:
             return Mode.PIPENV

tests/test_hooks.py

@@ -173,6 +173,12 @@ def test_poetry_mode(self):
 
         self.assertEqual(pre_commit_hook.read_mode(), Mode.POETRY)
 
+    def test_poetry_mode_with_python3(self):
+        path = FakeReadPath(f"#!{POETRY_SHEBANG}3")
+        pre_commit_hook = PreCommitHook(path)
+
+        self.assertEqual(pre_commit_hook.read_mode(), Mode.POETRY)
+
     def test_pipenv_multiline_mode(self):
         path = FakeReadPath(f"#!{PIPENV_MULTILINE_SHEBANG}")
         pre_commit_hook = PreCommitHook(path)