Update link to Zwavejs2Mqtt quick-start

[the-louie]

The orginal had captial Z and M where there shouldn't be.

Proposed change

Update URL to Zwave2Mqtt quick-guide

Type of change

Spelling mistake.

Additional information

There should be no capital letters in the url.

Checklist

• This PR uses the correct branch, based on one of the following:
  • I made a change to the existing documentation and used the current branch.
  • I made a change that is related to an upcoming version of Home Assistant and used the next branch.
• The documentation follows the Home Assistant documentation standards.

[MartinHjelmare]

Thanks!