Add CustomRecovery builtin middleware

[theonlyjohnny]

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CustomRecovery allows the user to control what happens in the case of a panic without having to re-implement the Recovery middleware

[codecov]

Codecov Report

Merging #2322 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2322   +/-   ##
=======================================
  Coverage   98.72%   98.72%           
=======================================
  Files          41       41           
  Lines        2348     2356    +8     
=======================================
+ Hits         2318     2326    +8     
  Misses         17       17           
  Partials       13       13           

Impacted Files	Coverage Δ
recovery.go	97.50% <100.00%> (+0.27%)	⬆️

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[theonlyjohnny]

👋 Could I get a maintainer's 👀 on this plz? Currently using my fork and would like to not have to

[thinkerou]

LGTM

[elftech]

why still no CustomRecovery in the recovery.go when I download v1.6.3 using go module?