Increase Chrome minimum version (#10019)

The Chrome minimum version has been increased from v58 to v63. We found
that we had very few users on versions below v63, and v62 is
incompatible with our SES lockdown dependency.

This also makes us compatible with Object rest/spread syntax, so we
might not have to transpile that anymore. I'll revisit that separately.

app/manifest/chrome.json

@@ -3,5 +3,5 @@
     "matches": ["https://metamask.io/*"],
     "ids": ["*"]
   },
-  "minimum_chrome_version": "58"
+  "minimum_chrome_version": "63"
 }

babel.config.js

@@ -6,7 +6,7 @@ module.exports = function (api) {
         '@babel/preset-env',
         {
           targets: {
-            browsers: ['chrome >= 58', 'firefox >= 56.2'],
+            browsers: ['chrome >= 63', 'firefox >= 56.2'],
           },
         },
       ],