add arm8 x64 builds to goreleaser

- Also fix goreleaser builds, as the earlier refactor broke it.
- Note: we disable x32 for darwin since that's an invalid pair

goreleaser.yml

@@ -1,20 +1,30 @@
 # https://github.com/goreleaser/goreleaser/blob/master/.goreleaser.yml
 build:
- main: .
+ main: ./cmd/main.go
  binary: zap
  goos:
  - darwin
  - linux
+ goarch:
+ - amd64
+ - 386
+ - arm64
+ ignore:
+ - goos: darwin
+ goarch: 386
+ ldflags:
+ - -s -w
 checksum:
  name_template: '{{ .ProjectName }}_checksums.txt'
 archives:
- - id: main
+ - id: cmd
  name_template: '{{ .ProjectName }}_{{ .Os }}_{{ .Arch }}'
  replacements:
  amd64: 64-bit
  386: 32-bit
  darwin: MacOS
  linux: Linux
+ arm64: Arm
  files:
  - c.yml
  - README.md