fix: github build error

README.md

@@ -175,9 +175,9 @@ export default FontFamilyStylesheet;
 ```javascript
 import FontFamilyStylesheet from 'stylesheet.js';
 
-<RichEditor
-  editorStyle={{ initialCSSText: `${FontFamilyStylesheet}`, contentCSSText: `font-family: 'Your Font Family';` }}
-/>
+const fontFamily = 'Your_Font_Family';
+const initialCSSText = { initialCSSText: `${FontFamilyStylesheet}`, contentCSSText: `font-family: ${fontFamily}` }
+<RichEditor editorStyle={initialCSSText}/>
 ```
 5. Reload the app. You should now be seeing your Rich Editor content in your custom font face!
 
@@ -293,6 +293,8 @@ import React from "react";
 import { Text, Platform, KeyboardAvoidingView, SafeAreaView, ScrollView } from "react-native";
 import {actions, RichEditor, RichToolbar} from "react-native-pell-rich-editor";
 
+
+const handleHead = ({tintColor}) => <Text style={{color: tintColor}}>H1</Text>
 const TempScreen = () => {
 	const richText = React.useRef();
 	return (
@@ -312,7 +314,7 @@ const TempScreen = () => {
       <RichToolbar
         editor={richText}
         actions={[ actions.setBold, actions.setItalic, actions.setUnderline, actions.heading1 ]}
-        iconMap={{ [actions.heading1]: ({tintColor}) => (<Text style={[{color: tintColor}]}>H1</Text>), }}
+        iconMap={{ [actions.heading1]: handleHead }}
       />
     </SafeAreaView>
   );

examples/src/example.tsx

@@ -4,7 +4,7 @@
  * @author wxik
  * @since 2019-06-24 14:52
  */
-import React, {useCallback, useEffect, useMemo, useRef, useState} from 'react';
+import {useCallback, useEffect, useMemo, useRef, useState} from 'react';
 import {
   Appearance,
   Button,