Fix font PropTypes

elements/TSpan.js

@@ -14,8 +14,8 @@ export default class extends Shape {
     static propTypes = {
         ...pathProps,
         ...fontProps,
-        dx: numberProp,
-        dy: numberProp,
+        dx: PropTypes.string,
+        dy: PropTypes.string,
     };
 
     static childContextTypes = {

elements/Text.js

@@ -13,8 +13,8 @@ export default class extends Shape {
     static propTypes = {
         ...pathProps,
         ...fontProps,
-        dx: numberProp,
-        dy: numberProp,
+        dx: PropTypes.string,
+        dy: PropTypes.string,
     };
 
     static childContextTypes = {

elements/TextPath.js

@@ -19,7 +19,7 @@ export default class extends Shape {
         href: PropTypes.string.isRequired,
         method: PropTypes.oneOf(['align', 'stretch']),
         spacing: PropTypes.oneOf(['auto', 'exact']),
-        startOffset: numberProp
+        startOffset: PropTypes.string
     };
 
     render() {