Add alert for changed REST response codes in 5.2.0

[Nadahar]

This is to notify users about the changes made in openhab/openhab-core#5236. I was waiting for a decision for openhab/openhab-core#5330 as well, but since nothing seems to happen there, I decided to get this done before I forget it.

[Nadahar]

@florian-h05 Is this sufficient/appropriate?

[florian-h05]

I'd put this before the corona stats entry and prefix it with CORE:

ALERT;CORE: GET /actions/{thingUID} REST API endpoint has changed HTTP status code from 404 to 204 if no entries exist
ALERT;CORE: GET /channel-types/{channelTypeUID} and GET /thing-types/{thingTypeUID} REST API endpoints have changed HTTP status code from 204 to 404 if no result is found

[Nadahar]

I'd put this before the corona stats entry and prefix it with CORE:

I have never seen how these alerts are presented, so I don't know what they produce. Are there "codes" that trigger a certain "presentation", or is it simply printed as-is as text?

[florian-h05]

They are presented as text while upgrading the package. The package scripts read them and print them. The first part (ALERT, WARNING) controls how they are presented (Color), the rest is just plain text.