build(deps-dev): Bump tslint from 5.20.1 to 6.1.2

Bumps [tslint](https://github.com/palantir/tslint) from 5.20.1 to 6.1.2.
- [Release notes](https://github.com/palantir/tslint/releases)
- [Changelog](https://github.com/palantir/tslint/blob/master/CHANGELOG.md)
- [Commits](palantir/tslint@5.20.1...6.1.2)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -31,7 +31,7 @@
     "semantic-release": "~17.0.7",
     "source-map-support": "~0.5.11",
     "ts-node": "~8.10.1",
-    "tslint": "~5.20.0",
+    "tslint": "~6.1.2",
     "typedoc": "~0.17.0",
     "typescript": "~3.9.2"
   },