fix: use @babel/polyfill in tests

package.json

@@ -9,6 +9,7 @@
   "description": "Buffer an AsyncIterator before iteration.",
   "devDependencies": {
     "@babel/core": "^7.0.0-beta.49",
+    "@babel/polyfill": "^7.0.0-beta.49",
     "@babel/preset-env": "^7.0.0-beta.49",
     "@babel/preset-flow": "^7.0.0-beta.49",
     "@commitlint/cli": "^7.0.0",
@@ -28,7 +29,8 @@
     "jest": "^23.1.0",
     "lint-staged": "^7.1.3",
     "prettier": "1.13.4",
-    "rimraf": "^2.6.2"
+    "rimraf": "^2.6.2",
+    "semantic-release": "^15.5.0"
   },
   "engines": {
     "node": ">=6"
@@ -49,7 +51,8 @@
     "lint": "flow && eslint . && prettier --l \"{__tests__,src}/**/*.js\"",
     "test": "yarn test:src && yarn build && yarn test:dist",
     "test:src": "jest --config scripts/jest/config.source.js",
-    "test:dist": "jest --config scripts/jest/config.dist.js"
+    "test:dist": "jest --config scripts/jest/config.dist.js",
+    "semantic-release": "semantic-release"
   },
-  "version": "0.0.0-semantic-release"
+  "version": "0.0.0-development"
 }

scripts/jest/config.source.js

@@ -1,6 +1,7 @@
 module.exports = {
   collectCoverageFrom: ['src/**/*.js', '!src/{index,types}.js'],
   rootDir: process.cwd(),
+  setupFiles: ['@babel/polyfill'],
   testEnvironment: 'node',
   testMatch: ['**/*.test.js'],
 };