add composer's vendor directory

vendor/symfony/yaml/CHANGELOG.md

@@ -0,0 +1,34 @@
+CHANGELOG
+=========
+
+3.0.0
+-----
+
+ * Yaml::parse() now throws an exception when a blackslash is not escaped
+   in double-quoted strings
+
+2.8.0
+-----
+
+ * Deprecated usage of a colon in an unquoted mapping value
+ * Deprecated usage of @, \`, | and > at the beginning of an unquoted string
+ * When surrounding strings with double-quotes, you must now escape `\` characters. Not
+   escaping those characters (when surrounded by double-quotes) is deprecated.
+
+   Before:
+
+   ```yml
+   class: "Foo\Var"
+   ```
+
+   After:
+
+   ```yml
+   class: "Foo\\Var"
+   ```
+
+2.1.0
+-----
+
+ * Yaml::parse() does not evaluate loaded files as PHP files by default
+   anymore (call Yaml::enablePhpParsing() to get back the old behavior)