Fixes warning for missing keys in color controls example

Author: Claudio Procida

examples/draft-0-10-0/color/color.html

@@ -146,6 +146,7 @@
           <div style={styles.controls}>
             {COLORS.map(type =>
               <StyleButton
+                key={type.label}
                 active={currentStyle.has(type.style)}
                 label={type.label}
                 onToggle={props.onToggle}

examples/draft-0-9-1/color/color.html

@@ -146,6 +146,7 @@
           <div style={styles.controls}>
             {COLORS.map(type =>
               <StyleButton
+                key={type.label}
                 active={currentStyle.has(type.style)}
                 label={type.label}
                 onToggle={props.onToggle}