README: Update CAN maintainer, also add Compass and Cube* maintainership

README.md

@@ -102,6 +102,9 @@ for reviewing patches on their specific area.
   - ***Subsystem***: DataFlash, Tools
 - [Randy Mackay](https://github.com/rmackay9):
   - ***Vehicle***: Copter, Rover, AntennaTracker
+- [Siddharth Purohit](https://github.com/bugobliterator):
+  - ***Subsystem***: CAN, Compass
+  - ***Board***: Cube*
 - [Tom Pittenger](https://github.com/magicrub):
   - ***Vehicle***: Plane
 - [Bill Geyer](https://github.com/bnsgeyer):
@@ -110,9 +113,6 @@ for reviewing patches on their specific area.
   - ***Vehicle***: TradHeli
 - [Emile Castelnuovo](https://github.com/emilecastelnuovo):
   - ***Board***: VRBrain
-- [Eugene Shamaev](https://github.com/EShamaev):
-  - ***Subsystem***: CAN bus
-  - ***Subsystem***: UAVCAN
 - [Georgii Staroselskii](https://github.com/staroselskii):
   - ***Board***: NavIO
 - [Gustavo José de Sousa](https://github.com/guludo):