Bump tslint from 5.20.0 to 5.20.1 (#2297)

Bumps [tslint](https://github.com/palantir/tslint) from 5.20.0 to 5.20.1.
- [Release notes](https://github.com/palantir/tslint/releases)
- [Changelog](https://github.com/palantir/tslint/blob/master/CHANGELOG.md)
- [Commits](palantir/tslint@5.20.0...5.20.1)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -60,7 +60,7 @@
     "mock-fs": "~4.10.3",
     "rewire": "~4.0.1",
     "sinon": "~7.5.0",
-    "tslint": "~5.20.0",
+    "tslint": "~5.20.1",
     "typescript": "~3.5.3",
     "vsce": "~1.64.0",
     "vscode": "~1.1.36"