Bump tslib from 2.6.3 to 2.8.1

Bumps [tslib](https://github.com/Microsoft/tslib) from 2.6.3 to 2.8.1.
- [Release notes](https://github.com/Microsoft/tslib/releases)
- [Commits](microsoft/tslib@v2.6.3...v2.8.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -54,7 +54,7 @@
     "moment": "^2.30.1",
     "moment-timezone": "^0.5.46",
     "rxjs": "^7.5.5",
-    "tslib": "^2.3.1",
+    "tslib": "^2.8.1",
     "vis-data": "^7.1.6",
     "vis-timeline": "^7.7.3",
     "zone.js": "~0.14.10"