chore(deps-dev): bump rollup from 0.67.4 to 0.68.0

Bumps [rollup](https://github.com/rollup/rollup) from 0.67.4 to 0.68.0.
- [Release notes](https://github.com/rollup/rollup/releases)
- [Changelog](https://github.com/rollup/rollup/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rollup/rollup/compare/v0.67.4...v0.68.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

web3.js/package-lock.json

@@ -13928,9 +13928,9 @@
       }
     },
     "rollup": {
-      "version": "0.67.4",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-0.67.4.tgz",
-      "integrity": "sha512-AVuP73mkb4BBMUmksQ3Jw0jTrBTU1i7rLiUYjFxLZGb3xiFmtVEg40oByphkZAsiL0bJC3hRAJUQos/e5EBd+w==",
+      "version": "0.68.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-0.68.0.tgz",
+      "integrity": "sha512-UbmntCf8QBlOqJnwsNWQCI0oonHOgs9y1OLoO8BHf2r8gCyRLp3JzLHXARJpsNDAS08Qm3LDjzyWma5sqnCxDQ==",
       "dev": true,
       "requires": {
         "@types/estree": "0.0.39",

web3.js/package.json

@@ -109,7 +109,7 @@
     "marked": "^0.5.1",
     "prettier": "^1.14.3",
     "rimraf": "2.6.2",
-    "rollup": "0.67.4",
+    "rollup": "0.68.0",
     "rollup-plugin-babel": "3.0.7",
     "rollup-plugin-commonjs": "9.2.0",
     "rollup-plugin-json": "^3.0.0",