caddyfile: accommodate unmarshaling of any new fields

[mohammed90]

Instead of eternally chasing new fields in the upstream log encoder, delegate unmarshalling those fields to upstream after taking action on our fields only. This should resolve #25 and prevent it from happening in the future.

Closes #25

[francislavoie]

I think you can update the README as well to point to the official docs for the remaining fields

[francislavoie]

I think you should have tests that put placeholder both before and/or after remaining fields to make sure ordering doesn't break it, and also multiple remaining ones.

[mohammed90]

I think you can update the README as well to point to the official docs for the remaining fields

Done

I think you should have tests that put placeholder both before and/or after remaining fields to make sure ordering doesn't break it, and also multiple remaining ones.

And Done!