[change] remove 'resizeMode' static from 'Image'

Use strings instead of the 'Image.resizeMode' static. Corresponding change in React Native:

https://github.com/facebook/react-native/commit/870775e

packages/react-native-web/src/exports/Image/__tests__/__snapshots__/index-test.js.snap

@@ -12,6 +12,8 @@ exports[`components/Image prop "resizeMode" value "cover" 1`] = `"cover"`;
 
 exports[`components/Image prop "resizeMode" value "none" 1`] = `"auto"`;
 
+exports[`components/Image prop "resizeMode" value "repeat" 1`] = `"auto"`;
+
 exports[`components/Image prop "resizeMode" value "stretch" 1`] = `"100% 100%"`;
 
 exports[`components/Image prop "resizeMode" value "undefined" 1`] = `"cover"`;

packages/react-native-web/src/exports/Image/__tests__/index-test.js

@@ -141,13 +141,7 @@ describe('components/Image', () => {
   });
 
   describe('prop "resizeMode"', () => {
-    [
-      Image.resizeMode.contain,
-      Image.resizeMode.cover,
-      Image.resizeMode.none,
-      Image.resizeMode.stretch,
-      undefined
-    ].forEach(resizeMode => {
+    ['contain', 'cover', 'none', 'repeat', 'stretch', undefined].forEach(resizeMode => {
       test(`value "${resizeMode}"`, () => {
         const component = shallow(<Image resizeMode={resizeMode} />);
         expect(findImageSurfaceStyle(component).backgroundSize).toMatchSnapshot();
@@ -214,7 +208,7 @@ describe('components/Image', () => {
 
   describe('prop "style"', () => {
     test('supports "resizeMode" property', () => {
-      const component = shallow(<Image style={{ resizeMode: Image.resizeMode.contain }} />);
+      const component = shallow(<Image style={{ resizeMode: 'contain' }} />);
       expect(findImageSurfaceStyle(component).backgroundSize).toMatchSnapshot();
     });
 

packages/react-native-web/src/exports/Image/index.js

@@ -132,8 +132,6 @@ class Image extends Component<*, State> {
     return ImageLoader.prefetch(uri);
   }
 
-  static resizeMode = ImageResizeMode;
-
   _filterId = 0;
   _imageRef = null;
   _imageRequestId = null;

packages/website/storybook/1-components/Image/ImageScreen.js

@@ -136,16 +136,6 @@ const ImageScreen = () => (
       />
     </Section>
 
-    <Section title="Properties">
-      <DocItem
-        name="static resizeMode"
-        typeInfo="object"
-        example={{
-          code: '<Image resizeMode={Image.resizeMode.contain} />'
-        }}
-      />
-    </Section>
-
     <Section title="Methods">
       <DocItem
         name="static getSize"