Bump flot from 0.8.3 to 4.2.2

Bumps [flot](https://github.com/flot/flot) from 0.8.3 to 4.2.2.
- [Release notes](https://github.com/flot/flot/releases)
- [Changelog](https://github.com/flot/flot/blob/master/CHANGELOG.md)
- [Commits](flot/flot@v0.8.3...v4.2.2)

---
updated-dependencies:
- dependency-name: flot
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -25,7 +25,7 @@
   "dependencies": {
     "bootstrap": "~3.4.0",
     "d3": "^3.5.4",
-    "flot": "~0.8.0-alpha",
+    "flot": "~4.2.2",
     "font-awesome": "~4.7.0",
     "http-server": "^13.0.1",
     "jquery": "^3.3.1",