Restore SPI metadata for non-module apps

[tschut]

Hi,

#283 removes SPI metadata which enables service discovery through Java's ServiceLoader. This information is now provided through module-info.

This new solution works fine if you're building a module-based application. However, if you don't use Java module-system (which many people don't), the services will no longer be auto-discovered.

As a widely-used library, it would be awesome if both method were supported.

[cowtowncoder]

Hmmh. Ok, that makes sense

Let me see how easy it'd be to restore SPI metadata first in 3.x (for 3.1.0) and if that goes well, backport in 3.0 (for 3.0.3).

[cowtowncoder]

Fixed for 3.0(.3), 3.1.0. LMK if things work if you can try out 3.0.3-SNAPSHOT?
(I am hoping to release 3.0.3 today or tomorrow)