Fix #302: babashka compatibility

[borkdude]

This PR relies on bb master which adds compatibility with malli. Fixes #302.

Notes:

• To make malli work well with bb, the :bb reader conditionals rely less on internal details of Clojure and use core functions instead, similar to what happens in :cljs branches. As discussed with @puredanger, I didn't add LazilyPersistentVector to bb as that was too far off from what is considered a public API.
• Upgrade borkdude/dynaload which was made compatible with bb
• Add bb test runner to ensure no breakage happens with future changes to malli
• The evaluation part is implemented by just using load-string in bb, since SCI itself isn't exposed yet (might happen in the future). SCI also has eval-form which lets you skip the string parsing bit, that might be more performant, but we can address that in a future PR.

@ikitommi I'm not sure what the workflow is with metosin/malli but I usually squash+merge the commits through the Github option (dropdown in merge button). If you want I can squash this PR manually as well.

If you want to try:

bash <(curl -s https://raw.githubusercontent.com/babashka/babashka/master/install) --version 0.8.157-SNAPSHOT --dir /tmp

for installing bb master in /tmp.
Then in a script:

(ns malli-test
  (:require [babashka.deps :as deps]))

(deps/add-deps '{:deps {metosin/malli
                        {:git/url "https://github.com/borkdude/malli"
                         :git/sha "1ec8582e3a39c8d170cf5f8a7482386bf66370fe"}}})

(require '[malli.core :as malli])

(prn (malli/validate [:map [:a [:int]]] {:a 1}))
(prn (malli/explain [:map [:a [:int]]] {:a "foo"}))

[borkdude]

Sorry, had to download bb master instead of using the setup-clojure one.

[ikitommi]

Looks great and agree on the design/implementation decisions. Happy to merge this - not squashing by default (one can track the merge commits from master), but the fact "This PR relies on bb master" - should I wait for a new release of bb first?

Update to README would be great. How do you promote a lib to be compliant with bb? is it a third target like this:

| Data-driven Schemas for Clojure/Script and Babashka.

... or just a feature:

| * Works with Babashka

If you have time to update the README, would love that. Will do that otherwise.

and, THANKS.

Tommi

[borkdude]

@ikitommi Addressed feedback: squashed commit and updated README.

You can see how the README looks here:

https://github.com/borkdude/malli/tree/babashka#babashka

If you will release 0.8.9 then I will release a new version of babashka. It doesn't matter who releases first.

[ikitommi]

💯