fix: change the keyboard appearance according to theme (#593)

If the dark theme is active, currently there is still a light keyboard shown (iOS).

Author: Dylan Companjen

src/components/Searchbar.js

@@ -156,6 +156,7 @@ class Searchbar extends React.Component<Props> {
           selectionColor={colors.primary}
           underlineColorAndroid="transparent"
           returnKeyType="search"
+          keyboardAppearance={dark ? 'dark' : 'light'}
           accessibilityTraits="search"
           accessibilityRole="search"
           ref={c => {