Bump popper.js from 1.16.0 to 1.16.1

Bumps [popper.js](https://github.com/FezVrasta/popper.js) from 1.16.0 to 1.16.1.
- [Release notes](https://github.com/FezVrasta/popper.js/releases)
- [Commits](https://github.com/FezVrasta/popper.js/commits)

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

package.json

@@ -12,7 +12,7 @@
     "jquery-ui": "^1.12.1",
     "jstree": "^3.3.8",
     "opensans-webkit": "^1.0.1",
-    "popper.js": "^1.15.0",
+    "popper.js": "^1.16.1",
     "snyk": "^1.279.1",
     "underscore": "^1.9.2",
     "vis": "^4.21.0",