add library information for PlatformIO

[Fixbruenix]

To be able to install the library from within PlatformIO, an information file is required which is added in this PR. If this PR is merged, the library also need to be published as described here. In case of success, we should also add installation instructions to the following pages I found (feel free to add more):

https://github.com/pschatzmann/arduino-audio-tools/wiki/Working-with-PlatformIO
https://github.com/pschatzmann/arduino-audio-tools/blob/main/README.md

[pschatzmann]

Thanks for your contribution, but I consider the version information in library.properties already a nuisance and I prefer that you rather rely on the git versioning. Adding another configuration file with version information does not help.

The Wiki describes how to use this library in PlatformIO and this allows you to specify the GIT version if you don't want to use the main branch

[Fixbruenix]

Thanks for the explanation.

Unfortunately, without this file (and the version information in it) it is not possible to find this library within the PlatformIO dependency management UI.

If your decision is based only on caring about the version number, maybe Github actions could help to keep it up to date.

[pschatzmann]

Did you have a look at the Wiki? You can easily add all my libraries in the lib_deps section of plaftormio.ini
Usually you would need some additional libraries: e.g. for the codecs or A2DP etc

The Wiki explains now how you can select a specific version

[Fixbruenix]

Yes, I did read (and link) the Wiki and I like your addition of today. The PR was about supporting the common way in PlatformIO, the UI of the dependency management. I understood that this is not intended for this library, at least not in this repository.

[pschatzmann]

Yes, this is currently out of scope: the AudioTools supports > 100 optional additional libraries and it would be a major undertaking to address all of them.