Upgrade babel to 52 and upgrade rollup (#624)

.size-snapshot.json

@@ -1,18 +1,18 @@
 {
   "dist/react-beautiful-dnd.js": {
-    "bundled": 351254,
-    "minified": 131924,
-    "gzipped": 36926
+    "bundled": 351293,
+    "minified": 131963,
+    "gzipped": 36950
   },
   "dist/react-beautiful-dnd.min.js": {
     "bundled": 311515,
     "minified": 114405,
     "gzipped": 31319
   },
   "dist/react-beautiful-dnd.esm.js": {
-    "bundled": 180820,
-    "minified": 93021,
-    "gzipped": 23027,
+    "bundled": 180859,
+    "minified": 93059,
+    "gzipped": 23047,
     "treeshaked": {
       "rollup": {
         "code": 68605,

package.json

@@ -58,14 +58,14 @@
   },
   "devDependencies": {
     "@atlaskit/css-reset": "^2.0.7",
-    "@babel/core": "^7.0.0-beta.51",
-    "@babel/plugin-proposal-class-properties": "^7.0.0-beta.51",
-    "@babel/plugin-proposal-object-rest-spread": "^7.0.0-beta.51",
-    "@babel/plugin-transform-modules-commonjs": "^7.0.0-beta.51",
-    "@babel/plugin-transform-runtime": "^7.0.0-beta.51",
-    "@babel/preset-env": "^7.0.0-beta.51",
-    "@babel/preset-flow": "^7.0.0-beta.51",
-    "@babel/preset-react": "^7.0.0-beta.51",
+    "@babel/core": "^7.0.0-beta.52",
+    "@babel/plugin-proposal-class-properties": "^7.0.0-beta.52",
+    "@babel/plugin-proposal-object-rest-spread": "^7.0.0-beta.52",
+    "@babel/plugin-transform-modules-commonjs": "^7.0.0-beta.52",
+    "@babel/plugin-transform-runtime": "^7.0.0-beta.52",
+    "@babel/preset-env": "^7.0.0-beta.52",
+    "@babel/preset-flow": "^7.0.0-beta.52",
+    "@babel/preset-react": "^7.0.0-beta.52",
     "@storybook/react": "^3.4.8",
     "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "^8.2.5",
@@ -95,8 +95,8 @@
     "react-dom": "^16.3.1",
     "react-test-renderer": "^16.3.1",
     "rimraf": "^2.6.2",
-    "rollup": "^0.61.2",
-    "rollup-plugin-babel": "^4.0.0-beta.5",
+    "rollup": "^0.62.0",
+    "rollup-plugin-babel": "^4.0.0-beta.7",
     "rollup-plugin-commonjs": "^9.1.3",
     "rollup-plugin-node-resolve": "^3.3.0",
     "rollup-plugin-replace": "^2.0.0",