use solhint-community (#25)

* use solhint-community fork

We're trying to keep solhint afloat with a fork, and done some work on
it so far, mainly the no-unused-imports rule.

Any feedback is appreciated, hope this helps ✨

see announcement:
https://blog.capu.tech/announcing-solhint-community.html

* docs: update README

---------

Co-authored-by: Paul Razvan Berg <paul.razvan.berg@gmail.com>

package.json

@@ -8,7 +8,7 @@
   },
   "devDependencies": {
     "prettier": "^2.8.7",
-    "solhint": "^3.4.0"
+    "solhint-community": "^3.5.0"
   },
   "keywords": [
     "blockchain",