Use lazy pmap for lazy-depth

[totakke]

com.climate.claypoole/pmap consumes extra elements, so that it is inappropriate for lazy sequence. Instead, cljam.algo.depth/lazy-depth uses com.climate.claypoole.lazy/pmap by this change.

lazy/pmap is inferior in speed to cp/pmap, but current cljam provides non-lazy depth function for performance. I think lazy/pmap is useful to handle returned lazy sequence of lazy-depth.

[codecov]

Codecov Report

Merging #102 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #102   +/-   ##
=======================================
  Coverage   84.94%   84.94%           
=======================================
  Files          60       60           
  Lines        3966     3966           
  Branches      400      400           
=======================================
  Hits         3369     3369           
  Misses        197      197           
  Partials      400      400

Impacted Files	Coverage Δ
src/cljam/algo/depth.clj	73.8% <100%> (ø)	⬆️

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[alumi]

You're absolutely right! Thank you!