crowdin: PyYAML yaml.load(input) deprecation

* YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated,
  as the default Loader is unsafe.
  Please read https://msg.pyyaml.org/load for full details
* Use yaml.safe_load(input) instead - we only use a small subset of YAML
  so this works as expected

* Test: Compared the results of yaml.load() and yaml.safe_load()

Change-Id: I8dc2006ac8e15f8d86cc75ae0d7853d032d60f54
diff --git a/crowdin_sync.py b/crowdin_sync.py
index d3de7a8..7111033 100755
--- a/crowdin_sync.py
+++ b/crowdin_sync.py
@@ -68,7 +68,7 @@
     for f in config_files:
         fh = open(f, "r")
         try:
-            config = yaml.load(fh)
+            config = yaml.safe_load(fh)
             for tf in config['files']:
                 if project_path in tf['source']:
                     target_path = tf['translation']