deps: add babel plugins for optional chaining and nullish coalescing

They are in Stage 3 and are already dependencies or the React Native preset.

References:
https://babeljs.io/docs/en/babel-plugin-proposal-optional-chaining
https://babeljs.io/docs/en/babel-plugin-proposal-nullish-coalescing-operator

package-lock.json

       }
     },
     "@babel/plugin-proposal-nullish-coalescing-operator": {
-      "version": "7.0.0",
-      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-nullish-coalescing-operator/-/plugin-proposal-nullish-coalescing-operator-7.0.0.tgz",
-      "integrity": "sha512-QIN3UFo1ul4ruAsjIqK43PeXedo1qY74zeGrODJl1KfCGeMc6qJC4rb5Ylml/smzxibqsDeVZGH+TmWHCldRQQ==",
+      "version": "7.4.4",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-nullish-coalescing-operator/-/plugin-proposal-nullish-coalescing-operator-7.4.4.tgz",
+      "integrity": "sha512-Amph7Epui1Dh/xxUxS2+K22/MUi6+6JVTvy3P58tja3B6yKTSjwwx0/d83rF7551D6PVSSoplQb8GCwqec7HRw==",
       "requires": {
         "@babel/helper-plugin-utils": "^7.0.0",
-        "@babel/plugin-syntax-nullish-coalescing-operator": "^7.0.0"
+        "@babel/plugin-syntax-nullish-coalescing-operator": "^7.2.0"
       }
     },
     "@babel/plugin-proposal-object-rest-spread": {
       }
     },
     "@babel/plugin-proposal-optional-chaining": {
-      "version": "7.0.0",
-      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.0.0.tgz",
-      "integrity": "sha512-7x8HLa71OzNiofbQUVakS0Kmg++6a+cXNfS7QKHbbv03SuSaumJyaWsfNgw+T7aqrJlqurYpZqrkPgXu0iZK0w==",
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.2.0.tgz",
+      "integrity": "sha512-ea3Q6edZC/55wEBVZAEz42v528VulyO0eir+7uky/sT4XRcdkWJcFi1aPtitTlwUzGnECWJNExWww1SStt+yWw==",
       "requires": {
         "@babel/helper-plugin-utils": "^7.0.0",
-        "@babel/plugin-syntax-optional-chaining": "^7.0.0"
+        "@babel/plugin-syntax-optional-chaining": "^7.2.0"
       }
     },
     "@babel/plugin-proposal-unicode-property-regex": {
       }
     },
     "@babel/plugin-syntax-nullish-coalescing-operator": {
-      "version": "7.0.0",
-      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-nullish-coalescing-operator/-/plugin-syntax-nullish-coalescing-operator-7.0.0.tgz",
-      "integrity": "sha512-oAJmMsAvTSIk9y0sZdU2S/nY44PEUuHN7EzNDMgbuR4e/OwyfR9lSmoBJBZ2lslFZIqhksrTt4i+av7uKfNYDw==",
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-nullish-coalescing-operator/-/plugin-syntax-nullish-coalescing-operator-7.2.0.tgz",
+      "integrity": "sha512-lRCEaKE+LTxDQtgbYajI04ddt6WW0WJq57xqkAZ+s11h4YgfRHhVA/Y2VhfPzzFD4qeLHWg32DMp9HooY4Kqlg==",
       "requires": {
         "@babel/helper-plugin-utils": "^7.0.0"
       }
       }
     },
     "@babel/plugin-syntax-optional-chaining": {
-      "version": "7.0.0",
-      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.0.0.tgz",
-      "integrity": "sha512-QXedQsZf8yua1nNrXSePT0TsGSQH9A1iK08m9dhCMdZeJaaxYcQfXdgHWVV6Cp7WE/afPVvSKIsAHK5wP+yxDA==",
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.2.0.tgz",
+      "integrity": "sha512-HtGCtvp5Uq/jH/WNUPkK6b7rufnCPLLlDAFN7cmACoIjaOOiXxUt3SswU5loHqrhtqTsa/WoLQ1OQ1AGuZqaWA==",
       "requires": {
         "@babel/helper-plugin-utils": "^7.0.0"
       }

package.json

     "@babel/plugin-proposal-class-properties": "7.1.0",
     "@babel/plugin-proposal-export-default-from": "7.0.0",
     "@babel/plugin-proposal-export-namespace-from": "7.0.0",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "7.4.4",
+    "@babel/plugin-proposal-optional-chaining": "7.2.0",
     "@babel/plugin-transform-flow-strip-types": "7.0.0",
     "@babel/preset-env": "7.1.0",
     "@babel/preset-flow": "7.0.0",

webpack.config.js

                 plugins: [
                     require.resolve('@babel/plugin-transform-flow-strip-types'),
                     require.resolve('@babel/plugin-proposal-class-properties'),
-                    require.resolve(
-                        '@babel/plugin-proposal-export-default-from'),
-                    require.resolve(
-                        '@babel/plugin-proposal-export-namespace-from')
+                    require.resolve('@babel/plugin-proposal-export-default-from'),
+                    require.resolve('@babel/plugin-proposal-export-namespace-from'),
+                    require.resolve('@babel/plugin-proposal-nullish-coalescing-operator'),
+                    require.resolve('@babel/plugin-proposal-optional-chaining')
                 ],
                 presets: [
                     [