Update test name

Author: andyexeter

test/WebpackConfig.js

@@ -98,7 +98,7 @@ describe('WebpackConfig object', () => {
             expect(config.publicPath).to.equal('https://example.com/');
         });
 
-        it('foo/ throws an exception', () => {
+        it('You can omit the opening slash, but get a warning', () => {
             const config = createConfig();
             config.setPublicPath('foo');