Update version number

[jatinhariani]

Recent changes like the graphql upgrade are not available in the pub.dev version of 0.0.25-alpha

[SimonIT]

I'm currently waiting on #70 for null safety to release a new version

[setu-dev]

Any update on this?

[SimonIT]

I hoped, that some users of the lib would test the state from master so I'm more sure that everything works. I will release a new version the next days (hopefully)