Migrate husky to v6

[DavideViolante]

I migrated husky to v6 and it seems to work for me, but review it please.
What I did:

• tried the husky migration tool but without success (I think it needed an husky config file not inside package json)
• installed husky v6 as dev dep
• run npx husky-init && npm install as docs states
  • the command created .husky folder with gitignore and an example pre-commit file and add to package json the prepare script
• edited pre-commit file adding npm test, it seems to execute everything to me, but let me know here if the command to execute is different
• tried a commit to check if pre-commit hook is executed, and it is
• bumped version
• to test: prepublishOnly hook? Other hooks?

[fb55]

Thanks for looking into this! Looks mostly good, but I'd like to keep lint-staged around.

[fb55]

Thanks so much @DavideViolante, great PR!