Check apps.yaml before restarting

[PianSom]

One very useful feature of modern HA is that it checks that the configuration is valid before restarting.

I had an issue with Predbat today where I amended my apps.yaml (actually to reflect a change to the Octopus integration) and included an error. I didn't spot that Predbat had failed for a few hours. Stupid user error.

It would useful if, when it spotted a changed apps.yaml, rather than immediately restarting Predbat instead checked (or offered a check) that the new version is valid.