drop python3.6 support

python 3.6 reached end of life on 2021-12-23

Committed via https://github.com/asottile/all-repos

tests/destroyed_symlinks_test.py

diff --git a/tests/destroyed_symlinks_test.py b/tests/destroyed_symlinks_test.py
index cde06cf..39c474a 100644
--- a/tests/destroyed_symlinks_test.py
+++ b/tests/destroyed_symlinks_test.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import os
 import subprocess