Add library.json for PlatformIO compatibility

[maxgerhardt]

Adds the library.json metadata file to this repository so that tinyfsm can be used in the PlatformIO build system and IDE (website) by means of declaring this repo as a library dependency.

PlatformIO is a versatile Python-based tool and VSCode extension that allows building for over 800 microcontroller boards of all different architectures and frameworks like Arduino, mbed-os, Zephyr, etc.

I've also ported the elevator example to Arduino and tested it on an Arduino Uno: https://github.com/maxgerhardt/tinyfsm-arduino-example

[digint]

thanks for contributing!

please move this to contrib/platformio/library.json (or similar)

I don't want to pollute this "tiny ;-)" project with configs from all sort of IDE's

[maxgerhardt]

please move this to contrib/platformio/library.json (or similar)
I don't want to pollute this "tiny ;-)" project with configs from all sort of IDE's

Sadly that can't be done -- the way PlatformIO works when downloading / using a library is that it scans the subfolders for the first occurance of the library manifest file (library.properties from the Arduino IDE or library.json specifically for PlatformIO) and then takes that subfolder as the library. If I were it to place in contrib/platformio/ and there would only be the library.json in it, it would just use that folder, and since the code isn't there, it would fail of course. The file needs to be at the level where the actual library starts, which is usually the top-level. I'd have to file a feature request to get that behavior changed or a field added to it.

But it's also the same with Arduino IDE libraries -- the library.properties file is in the root of the library folder, and noone puts it somewhere else. See e.g. any repository of any library listed at https://www.arduinolibraries.info/. Some PlatformIO users wish to however e.g. use libraries and packages which are nested inside another folder in the repo and expect it to be picked up, hence that behavior.

[digint]

squashed and merged in: 5030693

Thanks for contributing!