chore(deps-dev): bump rollup from 2.18.0 to 2.21.0 in /web3.js (#10988)

Bumps [rollup](https://github.com/rollup/rollup) from 2.18.0 to 2.21.0.
- [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/v2.18.0...v2.21.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

web3.js/package-lock.json

@@ -21672,9 +21672,9 @@
       }
     },
     "rollup": {
-      "version": "2.18.0",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.18.0.tgz",
-      "integrity": "sha512-LhuQQp3WpnHo3HlKCRrdMXpB6jdLsGOoXXSfMjbv74s5VdV3WZhkYJT0Z6w/EH3UgPH+g/S9T4GJrKW/5iD8TA==",
+      "version": "2.21.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.21.0.tgz",
+      "integrity": "sha512-BEGgy+wSzux7Ycq58pRiWEOBZaXRXTuvzl1gsm7gqmsAHxkWf9nyA5V2LN9fGSHhhDQd0/C13iRzSh4bbIpWZQ==",
       "dev": true,
       "requires": {
         "fsevents": "~2.1.2"

web3.js/package.json

@@ -124,7 +124,7 @@
     "marked": "^1.1.0",
     "prettier": "^2.0.0",
     "rimraf": "3.0.2",
-    "rollup": "2.18.0",
+    "rollup": "2.21.0",
     "rollup-plugin-babel": "^4.3.2",
     "rollup-plugin-commonjs": "^10.0.0",
     "rollup-plugin-copy": "^3.3.0",