Added: changelog entry for accept header for token request
Unreleased changes are available as `avenga/couper:edge` container.
+* **Added**
+ * `Accept: application/json` request header to the OAuth2 token request, in order to make the Github token endpoint respond with a JSON token response ([#307](https://github.com/avenga/couper/pull/307))
+
* **Changed**
* Organized log format fields for uniform access and upstream log ([#300](https://github.com/avenga/couper/pull/300))
