Fix CI workflow and badge (#35)

Author: remi

.github/workflows/ci.yaml

@@ -3,7 +3,7 @@ name: CI
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
     branches:
       - '**'

README.md

@@ -5,7 +5,7 @@
     <strong>React Native Killswitch</strong> is a library built by <a href="https://www.mirego.com">Mirego</a> that allows mobile developers to apply<br /> runtime version-specific behaviors to their React Native application.
   </p>
 
-  <a href="https://github.com/mirego/react-native-killswitch/actions/workflows/ci.yaml"><img src="https://github.com/mirego/react-native-killswitch/actions/workflows/ci.yaml/badge.svg" /></a>
+  <a href="https://github.com/mirego/react-native-killswitch/actions/workflows/ci.yaml"><img src="https://github.com/mirego/react-native-killswitch/actions/workflows/ci.yaml/badge.svg?branch=main" /></a>
   <a href="https://github.com/mirego/react-native-killswitch/tags"><img src="https://img.shields.io/npm/v/react-native-killswitch.svg"></a><br /><br />
 </div>