fix: Set unpkg default to feather.min.js 

style: Fix formatting 

fix: Remove unused polyfills and update build config Removes polyfills for `Object.assign` and `Set` which, as far as I can tell, are unused in the codebase. Updates `webpack` from 3 to 4. Replaces `babel-preset-es2015` with `babel-preset-env`. Reduces the minified bundle size (`feather.min.js`) by **9.3kB** (72.4kB to 63.1kB). Does not change any functionality of the library.

feat: Add `archive` icon 

feat: Add SVG sprite support (feathericons#319) 

fix: Fix semantic-release deploys Updated .travis.yml to match the example provided in the documentation https://semantic-release.gitbooks.io/semantic-release/content/docs/recipes/travis.html

feat: Add tags to tags.json 

feat: Add more tags 

feat: Add `linkedin` icon Closes feathericons#77

feat: Add more tags to tags.json