Improve pub.dev score

[Vardiak]

I feel that this repository should be more popular and be the de facto solution when building a socket.io application in dart, especially with Flutter.

Because of this issue, other repositories that are only an abstraction over socket.io-java and socket.io-swift are gaining more traction even though this package should be used instead.

I think it is explained by the bad scoring of this package on pub.dev which impact a lot on search ranking (link here). We should do something about it, because I feel that this package is really well made.

[jumperchen]

Yes, it's welcome to contribute it, if you would like to. :)

[jumperchen]

Now it got 95 score. :)