Bump tslib from 2.6.3 to 2.7.0

Bumps [tslib](https://github.com/Microsoft/tslib) from 2.6.3 to 2.7.0.
- [Release notes](https://github.com/Microsoft/tslib/releases)
- [Commits](microsoft/tslib@v2.6.3...v2.7.0)

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

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

package.json

@@ -27,7 +27,7 @@
     "rxjs": "~6.6.6",
     "stream": "0.0.2",
     "timers": "^0.1.1",
-    "tslib": "^2.6.3",
+    "tslib": "^2.7.0",
     "xmlbuilder2": "^2.4.1",
     "xmlrpc": "^1.3.2",
     "zone.js": "^0.14.7"