Pass keys to tag readers via opts.

[ccidral]

Passes the key path to tag readers as :key-path in the opts map.

An example of use case for this is a #required tag reader that throws an exception when the value is nil. The key path needs to be included in the exception message to indicate which key in configuration is the offending key. So if we have a configuration like:

{:a {:b {:c #required #env "FOO"}}}

It would throw an exception with a message like Required key [:a :b :c].

[codecov-commenter]

Codecov Report

Merging #103 (5108c67) into master (743e9bc) will increase coverage by 0.27%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #103      +/-   ##
==========================================
+ Coverage   79.13%   79.41%   +0.27%     
==========================================
  Files           4        4              
  Lines         369      374       +5     
  Branches       17       17              
==========================================
+ Hits          292      297       +5     
  Misses         60       60              
  Partials       17       17              

Impacted Files	Coverage Δ
src/aero/core.cljc	75.00% <100.00%> (+0.52%)	⬆️

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