feat: add isKeptAwake method

[robingenz]

Is your feature request related to a problem? Please describe.
Currently there is no way to check if the device is kept awake.

Describe the solution you'd like
Add isKeptAwake method.

Describe alternatives you've considered
No alternative solutions.

Additional context

[jansgescheit]

@robingenz is there any release date for this feature?

[robingenz]

@jansgescheit This feature will be officially released with Capacitor 5 support.

This is an untested development version for Capacitor 4 that you can try:

npm i @capacitor-community/keep-awake@3.0.0-dev.a4d5a8d.1683032576

[jansgescheit]

hmm too bad. I don't necessarily want to upgrade to Capacitor 5 for this feature - since there are no dependencies to Capacitor 5 in my eyes. Then I will solve this somehow differently.

[robingenz]

@jansgescheit What is wrong with the dev version? It supports Capacitor 4.

[jansgescheit]

@robingenz Probably nothing, but I don't want to use a dev version for production apps. I had been looking forward to this because the readme already praises this feature, but it is not included.