update to babel 7 + other dependencies

Author: scurker

.babelrc

@@ -1,6 +1,6 @@
 {
   "presets": [
-    ["babel-preset-env", {
+    ["@babel/preset-env", {
       targets: {
         browsers: ['last 2 versions'],
         node: 4
@@ -14,7 +14,7 @@
   "env": {
     "test": {
       "presets": [
-        ["babel-preset-env", {
+        ["@babel/preset-env", {
           targets: {
             node: 'current'
           }

.browserslistrc

@@ -0,0 +1,2 @@
+last 2 versions
+> 1%

ava.config.js

@@ -0,0 +1,3 @@
+export default {
+  require: ['@babel/register']
+};

config/rollup.umd.js

@@ -9,8 +9,7 @@ export default [{
   input,
   plugins: [
     babel({
-      exclude: 'node_modules/**',
-      plugins: ['transform-object-assign']
+      exclude: 'node_modules/**'
     })
   ],
   output: [
@@ -23,11 +22,10 @@ export default [{
   ]
 },
 {
-  input: 'src/currency.js',
+  input,
   plugins: [
     babel({
-      exclude: 'node_modules/**',
-      plugins: ['transform-object-assign']
+      exclude: 'node_modules/**'
     }),
     closure({
       compilationLevel: 'SIMPLE',