check eof before read bytes

[johnnychen94]

#345 is introduced by #343. It turns out that seek is not defined for GZip stream object GzipDecompressor, so here it uses a per-byte strategy to check the io length.

This is a bug fix so I'll merge quickly and tag a patch version for it.

fixes #345

cc: @jonasjonker @alyst

[codecov]

Codecov Report

Merging #346 (834037a) into master (01b504d) will decrease coverage by 0.20%.
The diff coverage is 80.95%.

@@            Coverage Diff             @@
##           master     #346      +/-   ##
==========================================
- Coverage   88.29%   88.09%   -0.21%     
==========================================
  Files          10       10              
  Lines         641      655      +14     
==========================================
+ Hits          566      577      +11     
- Misses         75       78       +3     

Impacted Files	Coverage Δ
src/registry.jl	89.65% <80.95%> (-1.60%)	⬇️
src/query.jl	96.77% <0.00%> (+0.80%)	⬆️

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