Open up the coercion stack

[cddr]

A few people have noticed that the JSON representation of an avro object is a bit different to the edn representation of an avro object. This behaviour was originally copied from the abracad.avro project but it makes it a little bit inconvenient to work with data obtained via more "avro-oriented" tools like the kafka-avro-console-consumer or the avro-random-generator.

The pair of functions in this PR make it a bit easier to convert between these two representations.

Example Usage

as-json

(as-json {:avro-schema (clojure.data.json/write-str ["null" "string"])}
          "yolo")
=> "{\"string\":\"yolo\"}"

as-edn

(as-edn {:avro-schema (clojure.data.json/write-str ["null" "string"])}
        "{\"string\":\"yolo\"}")
=> "yolo"

Checklist

• [x] factor out the common code that builds the coercion-stack
• [x] tests
• [x] updated CHANGELOG (the "unreleased" section)

[codecov[bot]]

Codecov Report

Merging #224 into master will decrease coverage by 0.22%. The diff coverage is 96.96%.

@@            Coverage Diff             @@
##           master     #224      +/-   ##
==========================================
- Coverage   79.97%   79.74%   -0.23%     
==========================================
  Files          42       42              
  Lines        2597     2622      +25     
  Branches      150      151       +1     
==========================================
+ Hits         2077     2091      +14     
- Misses        370      380      +10     
- Partials      150      151       +1

Impacted Files	Coverage Δ
src/jackdaw/serdes/avro.clj	88.5% <96.96%> (+0.58%)	:arrow_up:
src/jackdaw/serdes/edn2.clj	45.45% <0%> (-45.46%)	:arrow_down:

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[AndreaCrotti]

No tests yet.

You can remove that from the description of the PR since you added them