Add Scala 2.11 support back

[softinio]

Scala 2.11 was removed in #89

Lets add it back now thar ZIO-NIO supports 2.11

[landlockedsurfer]

Hi!
I gave this a quick try and found out that there is one more dependency that currently does not support 2.11.
As per
https://mvnrepository.com/artifact/org.tpolecat/doobie-core
doobie has stopped supporting 2.11 since 0.8.2.

[DamianReeves]

Isn't doobie only used for a specific implementation of a service. Can we perhaps either leave it out, or just build with the old version, which-ever is easier?

[landlockedsurfer]

Hi Damian!
What I've seen is that the doobie dependencies are used in zioActorsPersistenceJDBC.
I found more details here:
https://zio.github.io/zio-actors/docs/overview/overview_persistence