README: Add known bugs

Author: DhruvaG2000

README.md

@@ -29,6 +29,10 @@ $ git clone git@github.com:arduino/ArduinoCore-API # Any location
 $ ln -s /<your>/<location>/ArduinoCore-API/api cores/arduino/.
 ```
 
+**Known Bugs:**
+While compiling with the ArduinoCore-API `WCharacter.h` produces many errors. It needs to be deleted from ArduinoAPI.h (it is unused in this port.) We are looking into resolving the issue.
+
+
 **Maintainers**:
 - beriberikix
 - szczys 
@@ -37,4 +41,4 @@ $ ln -s /<your>/<location>/ArduinoCore-API/api cores/arduino/.
 **Contributor**: [DhruvaG2000](https://github.com/DhruvaG2000)
 
 ## License
-Please note that the current license is Apache 2. Previously it was LGPL 2.1 but after careful review it was determined that no LGPL code or derivates was used and the more permissive license was chosen.
+Please note that the current license is Apache 2. Previously it was LGPL 2.1 but after careful review it was determined that no LGPL code or derivates was used and the more permissive license was chosen.