chore: Release miniconf version 0.20.1

chore: Release miniconf version 0.20.0

chore: Release miniconf_mqtt version 0.20.0

chore: Release miniconf_derive version 0.20.0

Merge pull request #288 from quartiq/release-v0.19.0

v0.19.0 chores

Merge pull request #270 from quartiq/py-client

py: fix json loads on get/clear

Merge pull request #269 from quartiq/py-qol

py qol

Merge pull request #266 from quartiq/release-v0.18.0

release v0.18.0

Merge pull request #263 from quartiq/release-v0.17.2

release v0.17.2

Merge pull request #260 from quartiq/release-0.17.1

release 0.17.1