Bump handlebars from 4.7.6 to 4.7.7 in /server

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.7.6 to 4.7.7.
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/handlebars-lang/handlebars.js/blob/master/release-notes.md)
- [Commits](handlebars-lang/handlebars.js@v4.7.6...v4.7.7)

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

server/package.json

@@ -37,7 +37,7 @@
         "express-session": "^1.17.1",
         "follow-redirects": "^1.13.0",
         "geojson-validation": "^1.0.2",
-        "handlebars": "^4.7.6",
+        "handlebars": "^4.7.7",
         "handlebars-loader": "^1.7.1",
         "html-table-to-json": "^1.0.0",
         "http-proxy-middleware": "^1.0.5",