SG-30649 Specify 'utf8' encoding when read YAML data from disk. (#881)

* Specify utf8 encoding when read YAML data from disk.
* Turn off Hound's 'Black would make changes' msg.
* Use double quoting in the encoding parameter value and store  Hound's black check.

python/tank/util/yaml_cache.py

@@ -256,7 +256,7 @@ def _populate_cache_item_data(self, item):
         """
         path = item.path
         try:
-            with open(path, "r") as fh:
+            with open(path, "r", encoding="utf8") as fh:
                 raw_data = yaml.load(fh, Loader=yaml.FullLoader)
         except IOError:
             raise TankFileDoesNotExistError("File does not exist: %s" % path)