Apply common project tweaks (round 2) (#21)

* Add dependency-check

* Add Donate section and badges to README.md

* Tweak badges and links in README.md

README.md

@@ -2,14 +2,15 @@
 
 > Error module for [levelup][levelup]
 
-[![level badge][level-badge]](https://github.com/level/awesome)
-[![npm](https://img.shields.io/npm/v/level-errors.svg)](https://www.npmjs.com/package/level-errors)
-![Node version](https://img.shields.io/node/v/level-errors.svg)
-[![Build Status](https://travis-ci.org/Level/errors.svg)](https://travis-ci.org/Level/errors)
-[![dependencies](https://david-dm.org/Level/level.svg)](https://david-dm.org/level/level)
+[![level badge][level-badge]](https://github.com/Level/awesome)
+[![npm](https://img.shields.io/npm/v/level-errors.svg?label=&logo=npm)](https://www.npmjs.com/package/level-errors)
+[![Node version](https://img.shields.io/node/v/level-errors.svg)](https://www.npmjs.com/package/level-errors)
+[![Travis](https://img.shields.io/travis/Level/errors.svg?logo=travis&label=)](https://travis-ci.org/Level/errors)
 [![Coverage Status](https://coveralls.io/repos/github/Level/errors/badge.svg)](https://coveralls.io/github/Level/errors)
 [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
-[![npm](https://img.shields.io/npm/dm/level-errors.svg)](https://www.npmjs.com/package/level-errors)
+[![npm](https://img.shields.io/npm/dm/level-errors.svg?label=dl)](https://www.npmjs.com/package/level-errors)
+[![Backers on Open Collective](https://opencollective.com/level/backers/badge.svg?color=orange)](#backers)
+[![Sponsors on Open Collective](https://opencollective.com/level/sponsors/badge.svg?color=orange)](#sponsors)
 
 ## API
 
@@ -54,10 +55,22 @@ Error encoding data.
 
 See the [Contribution Guide](https://github.com/Level/community/blob/master/CONTRIBUTING.md) for more details.
 
+## Donate
+
+To sustain [`Level`](https://github.com/Level) and its activities, become a backer or sponsor on [Open Collective](https://opencollective.com/level). Your logo or avatar will be displayed on our 28+ [GitHub repositories](https://github.com/Level), [npm](https://www.npmjs.com/) packages and (soon) [our website](http://leveldb.org). 💖
+
+### Backers
+
+[![Open Collective backers](https://opencollective.com/level/backers.svg?width=890)](https://opencollective.com/level)
+
+### Sponsors
+
+[![Open Collective sponsors](https://opencollective.com/level/sponsors.svg?width=890)](https://opencollective.com/level)
+
 ## License
 
 [MIT](LICENSE.md) © 2012-present [Contributors](CONTRIBUTORS.md).
 
 [level-badge]: http://leveldb.org/img/badge.svg
 
-[levelup]: https://github.com/level/levelup
+[levelup]: https://github.com/Level/levelup

package.json

@@ -7,13 +7,16 @@
   "scripts": {
     "test": "standard && hallmark && nyc node test.js",
     "coverage": "nyc report --reporter=text-lcov | coveralls",
-    "hallmark": "hallmark --fix"
+    "hallmark": "hallmark --fix",
+    "dependency-check": "dependency-check . test.js",
+    "prepublishOnly": "npm run dependency-check"
   },
   "dependencies": {
     "errno": "~0.1.1"
   },
   "devDependencies": {
     "coveralls": "^3.0.2",
+    "dependency-check": "^3.3.0",
     "hallmark": "^0.1.0",
     "level-community": "^3.0.0",
     "nyc": "^12.0.2",
@@ -26,7 +29,7 @@
   "typings": "errors.d.ts",
   "repository": {
     "type": "git",
-     "url": "https://github.com/Level/errors.git"
+    "url": "https://github.com/Level/errors.git"
   },
   "homepage": "https://github.com/Level/errors",
   "keywords": [