Update jest esm (#35)

* chore(package): update jest to version 22.0.4

Closes #32

* chore(travis): instruct yarn to ignore engines

* chore(lockfile): update yarn lockfile

* chore(package): update @std/esm to version 0.19.0

* chore(package): update @std/esm to version 0.19.1

* test(jest): use node as testEnvironment

.travis.yml

@@ -8,6 +8,8 @@ node_js:
 cache: yarn
 matrix:
   fast_finish: true
+env:
+  - YARN_IGNORE_ENGINES=true
 
 after_success:
   - yarn add coveralls

package.json

@@ -23,15 +23,15 @@
     "prepublishOnly": "npm run lint && npm run test"
   },
   "dependencies": {
-    "@std/esm": "^0.18.0",
+    "@std/esm": "^0.19.1",
     "lodash": "^4.17.4",
     "postcss": "^6.0.1",
     "postcss-value-parser": "^3.3.0"
   },
   "devDependencies": {
     "babel-preset-env": "^1.5.1",
     "cross-env": "^5.0.0",
-    "jest": "^21.2.1",
+    "jest": "^22.0.4",
     "pre-commit": "^1.2.2",
     "standard": "^10.0.0",
     "yaspeller-ci": "^1.0.0"
@@ -42,6 +42,7 @@
     "cjs": true
   },
   "jest": {
-    "collectCoverage": true
+    "collectCoverage": true,
+    "testEnvironment": "node"
   }
 }