Merge branch 'patch-8' into 'master'

Update changelog.md

See merge request flatland/flatland!162

changelog.md

@@ -5,10 +5,23 @@
 The stock `ShortestPathPredictorForRailEnv` now respects the different agent speeds and updates their prediction accordingly.
 
 ### Changes in stock observation biulders
+
 - `TreeObsForRailEnv` now has **11** features!
     - 10th feature now indicates if a malfunctioning agent has been detected and how long the malfunction will still be present
     - 11th feautre now indicates the minimal observed fractional speed of agents traveling in the same direction
+- `GlobalObsForRailEnv` now has new features!
+    - Targets and other agent targets still represented in same way
+    - `obs_agents_state` now contains 4 channels
+        - 0th channel -> agent direction at agent position
+        - 1st channel -> other agents direction at their positions
+        - 2nd channel -> all agent malfunction duration at their positions
+        - 3rd channel -> all agent fractional speeds at their positions
+- `LocalObsForRailEnv` was not update to Flatland 2.0 because it was never used by participants of the challenge.
+
+
 ### Changes in level generation
+
+
 - Separation of `schedule_generator` from `rail_generator`: 
   - Renaming of `flatland/envs/generators.py` to `flatland/envs/rail_generators.py`
   - `rail_generator` now only returns the grid and optionally hints (a python dictionary); the hints are currently use for distance_map and communication of start and goal position in complex rail generator.