Change call_phone to callPhone to match convention.

Author: Chuong Le

README.md

@@ -121,7 +121,7 @@ Promises resolve into one of these statuses
 |`backgroundRefresh`| ✔️ | ❌ |
 |`speechRecognition`| ✔️ | ❌ |
 |`storage`| ❌️ | ✔ |
-|`call_phone`| ❌️ | ✔ |
+|`callPhone`| ❌️ | ✔ |
 
 ### Methods
 | Method Name | Arguments | Notes