chore(*): use Yarn 2 (#733)

* Migrate to Yarn 2

* Add peer deps

* Work

* prettify

* test

* this

* Clean up travis.yml

* Run prettier first

.eslintignore

@@ -7,3 +7,4 @@ build
 coverage
 node_modules
 __snapshots__
+.yarn/*

.gitignore

@@ -9,3 +9,10 @@ coverage
 .idea
 .eslintcache
 !packages/redux-devtools-slider-monitor/examples/todomvc/dist/index.html
+.yarn/*
+!.yarn/patches
+!.yarn/releases
+!.yarn/plugins
+!.yarn/sdks
+!.yarn/versions
+.pnp.*

.prettierignore

@@ -8,3 +8,4 @@ coverage
 node_modules
 __snapshots__
 dev
+.yarn/*

.travis.yml

@@ -1,13 +1,8 @@
-sudo: false
 language: node_js
 node_js:
   - 'stable'
-cache:
-  yarn: true
-  directories:
-    - 'node_modules'
 script:
+  - yarn prettier:check
   - yarn build:all
   - yarn lint:all
-  - yarn prettier:check
   - yarn test:all

.yarnrc.yml

@@ -0,0 +1,7 @@
+nodeLinker: node-modules
+
+plugins:
+  - path: .yarn/plugins/@yarnpkg/plugin-interactive-tools.cjs
+    spec: '@yarnpkg/plugin-interactive-tools'
+
+yarnPath: .yarn/releases/yarn-berry.cjs