Added notice about Buster

[codeclinic]

PiHole is currently unavailable in Buster. Since this is an ongoing issues that has no resolution eta, it's worth pointing out to people as it will save them some time. It may also lead to one or two people nudging the PiHole devs to look into the issue.

Description

Related issue (if applicable): Fixes #

Checklist

New suite

• [ ] The code change is tested and works locally.
• [ ] The code is compliant with Contributing guidelines
• [ ] Script has validation check of the job.
• [ ] Created documentation at /docs/suites

Change to existing suite

• [ ] The code change is tested and works locally.
• [ ] The code is compliant with Contributing guidelines
• [ ] Updated documentation at /docs/suites

New function

• [ ] The code change is tested and works locally.
• [ ] The code is compliant with Contributing guidelines
• [ ] Script has validation check of the job.
• [ ] Created documentation at /docs/cli

Change to existing function

• [x] The code change is tested and works locally.
• [x] The code is compliant with Contributing guidelines
• [x] Updated documentation at /docs/cli

[homeassistant]

Hi @codeclinic,

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[Landrash]

Seems like a good idea. Thank you.