Fix several ResourceWarning: unclosed file

pre_commit/commands/autoupdate.py

@@ -72,7 +72,8 @@ REV_LINE_FMT = '{}rev:{}{}{}'
 
 
 def _write_new_config_file(path, output):
-    original_contents = open(path).read()
+    with open(path) as f:
+        original_contents = f.read()
     output = remove_defaults(output, CONFIG_SCHEMA)
     new_contents = ordered_dump(output, **C.YAML_DUMP_KWARGS)
 

pre_commit/commands/install_uninstall.py

@@ -38,7 +38,8 @@ def _hook_paths(git_root, hook_type):
 def is_our_script(filename):
     if not os.path.exists(filename):
         return False
-    contents = io.open(filename).read()
+    with io.open(filename) as f:
+        contents = f.read()
     return any(h in contents for h in (CURRENT_HASH,) + PRIOR_HASHES)