Add gzip codec

[myzie]

>>> encode("TEST", "gzip")
byte_slice("\x1f\x8b\b\x00\x00\x00\x00\x00\x00\xff\nq\r\x0e\x01\x04\x00\x00\xff\xff\xb8\x93\xea\xee\x04\x00\x00\x00")
>>> encode("TEST", "gzip") | decode("gzip")
byte_slice("TEST")

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 31.35%. Comparing base (21602e4) to head (aed01ab).

Files	Patch %	Lines
builtins/codecs.go	50.00%	6 Missing and 6 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #200      +/-   ##
==========================================
+ Coverage   30.97%   31.35%   +0.38%     
==========================================
  Files         113      113              
  Lines       14505    14529      +24     
==========================================
+ Hits         4493     4556      +63     
+ Misses       9461     9398      -63     
- Partials      551      575      +24     

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