feat(updates): configure renovate

[casdr]

When Renovate is enabled for this repository and this PR is merged, Renovate will be configured to automatically create a PR whenever a new LibreNMS release is published.

An example can be seen at casdr#3

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ casdr
❌ renovate[bot]
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[laf]

Thanks for this @casdr .

I'm good with merging in and enabling Renovate. @crazy-max?

[casdr]

If accepted, the renovate[bot] username should also be added to the https://cla-assistant.io exclusion list.