chore(package): update @babel/plugin-proposal-nullish-coalescing-operator to version 7.10.1

Closes #115

Author: greenkeeper[bot]

package.json

@@ -68,7 +68,7 @@
     "@babel/plugin-proposal-function-sent": "7.10.1",
     "@babel/plugin-proposal-json-strings": "7.10.1",
     "@babel/plugin-proposal-logical-assignment-operators": "7.10.1",
-    "@babel/plugin-proposal-nullish-coalescing-operator": "7.8.3",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "7.10.1",
     "@babel/plugin-proposal-numeric-separator": "7.8.3",
     "@babel/plugin-proposal-optional-chaining": "7.9.0",
     "@babel/plugin-proposal-pipeline-operator": "7.8.3",