build: use gox and ghr instead of goreleaser

[suzuki-shunsuke]

No description provided.

[codecov]

Codecov Report

Merging #8 into master will decrease coverage by 2.64%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master       #8      +/-   ##
==========================================
- Coverage   75.13%   72.48%   -2.65%     
==========================================
  Files          91       95       +4     
  Lines        3471     3631     +160     
==========================================
+ Hits         2608     2632      +24     
- Misses        524      658     +134     
- Partials      339      341       +2

Impacted Files	Coverage Δ
index_set.go	100% <ø> (ø)	⬆️
mockserver/exec/main.go	19.71% <ø> (ø)
validator/validator.go	55.55% <0%> (ø)
terraform/main.go	0% <0%> (ø)
mockserver/seed/seed.go	0% <0%> (ø)

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