fix linter errors and run lint tests on CI too

Author: vaibhavhrt

.travis.yml

@@ -9,5 +9,5 @@ install:
   - yarn install
   - yarn add react prop-types
 script:
-  # - npm run lint
+  - yarn run lint
   - yarn test

src/index.ts

@@ -1,7 +1,7 @@
-import Star from "./star";
 import Fork from "./fork";
+import Sponsor from "./sponsor";
+import Star from "./star";
+import UsedBy from "./usedBy";
 import Watch from "./watch";
-import UsedBy from './usedBy';
-import Sponsor from './sponsor';
 
 export { Fork, Sponsor, Star, UsedBy, Watch };

src/usedBy.tsx

@@ -7,17 +7,17 @@ import * as React from "react";
 import GithubButton from "./lib/githubButton";
 
 export interface IPropTypes {
+  count: number;
   owner: string;
   repo: string;
-  count: number;
 }
 
 export default function UsedBy(props: IPropTypes) {
   return <GithubButton variant="usedby" { ...props } />;
 }
 
 UsedBy.propTypes = {
+  count: PropTypes.number.isRequired,
   owner: PropTypes.string.isRequired,
   repo: PropTypes.string.isRequired,
-  count: PropTypes.number.isRequired,
 };