Add VcrStorage abstraction

[exoego]

Closes #22

This PR introduces VcrStorage abstraction.
The trait abstract "reading record from somewhere" and "writing record to somewhere".

Codec trait is also introduced.
It abstract how VcrEntries is

• encoded from JSON, YAML or whatever, and
• decoded to JSON, YAML or whatever

This abstraction helps #3

[reibitto]

You're very quick with these 😂 Thanks!

I only noticed now, but it seems like the java: [11, 8] matrix in the the GitHub Actions workflow is not doing what was intended. Even the one marked as 11 is actually using 8:

[info] welcome to sbt 1.5.0 (AdoptOpenJDK Java 1.8.0_275)

It might be because olafurpg/setup-scala@v10 does its own setup?

[exoego]

Ah, I will look into jdk setup issues

[exoego]

Maybe implicit parameter is better to allow switching format (codec) to YAML or other?

  def apply(recordingPath: Path)(implicit codec: Codec): FileVcrStorage =
    new FileVcrStorage(recordingPath, codec, StandardCharsets.UTF_8)

[reibitto]

I'm not sure if it needs to be implicit. Maybe even default parameters (default of json) could work? I know some people don't like default parameters, but I'm already using them in the clients.

Also, maybe CirceCodec should be renamed to JsonCodec? Because circe also has a yaml library (https://github.com/circe/circe-yaml), which I imagine would be natural to use in this library. So we'd also have a YamlCodec in the future, right?

[exoego]

Renamed to JsonCodec 7698613
And introduced default parameters 48c9df0

[reibitto]

Thank you. This looks good to me.

I think I can release the first version of this library tomorrow. I just need to update all the examples, add more scaladocs, and then add a few more tests.