Added AssetsAudioPlayer

[florent37]

You've read How to contribute right ?

So tell me more about your awesome contribution and add the badge to your repo after it's accepted :D

<a href="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/Solido/awesome-flutter">
   <img alt="Awesome Flutter" src="https://img.shields.io/badge/Awesome-Flutter-blue.svg?longCache=true&style=flat-square" />
</a>

As you asked me here florent37/Flutter-AssetsAudioPlayer#157

I would like to add AssetsAudioPlayer to awesome-flutter

flutter:
  assets:
    - assets/audios/

AssetsAudioPlayer.newPlayer().open(
    Audio("assets/audios/song1.mp3"),
    autoPlay: true,
    showNotification: true,
);

[orestesgaolin]

Thanks for the PR! Please note that you shouldn't make changes directly to README.md but SOURCE.md. Take a look at the contribution guide here.

Feel free to close this PR and create new one to SOURCE.md

[florent37]

oh yes sorry, I recreate this

[florent37]

done #695