Build(deps): Bump tslib from 2.3.1 to 2.4.0 (#2540)

Bumps [tslib](https://github.com/Microsoft/tslib) from 2.3.1 to 2.4.0.
- [Release notes](https://github.com/Microsoft/tslib/releases)
- [Commits](https://github.com/Microsoft/tslib/compare/2.3.1...2.4.0)

---
updated-dependencies:
- dependency-name: tslib
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -53,7 +53,7 @@
     "moment-es6": "1.0.0",
     "pdfjs-dist": "2.5.207",
     "rxjs": "^6.6.3",
-    "tslib": "^2.3.1",
+    "tslib": "^2.4.0",
     "zone.js": "~0.10.2"
   },
   "devDependencies": {