Bump leaflet from 1.5.1 to 1.6.0

Bumps [leaflet](https://github.com/Leaflet/Leaflet) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/Leaflet/Leaflet/releases)
- [Changelog](https://github.com/Leaflet/Leaflet/blob/master/CHANGELOG.md)
- [Commits](Leaflet/Leaflet@v1.5.1...v1.6.0)

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

Author: dependabot-preview[bot]

package.json

@@ -118,7 +118,7 @@
     "fetch-ie8": "1.5.0",
     "fetch-jsonp": "1.0.6",
     "jsonsql": "0.2.5",
-    "leaflet": "1.5.1",
+    "leaflet": "1.6.0",
     "lodash.remove": "^4.7.0",
     "lodash.topairs": "4.3.0",
     "mapbox-gl": "1.3.1",