build: Remove unsupported build targets (#133)

Author: wata727

.goreleaser.yml

@@ -3,18 +3,15 @@
 env:
   - CGO_ENABLED=0
 builds:
-  - goos:
-      - linux
-      - darwin
-      - freebsd
-      - netbsd
-      - openbsd
-      - windows
-    goarch:
-      - 386
-      - amd64
-      - arm
-      - arm64
+  - targets:
+      - darwin_amd64
+      - darwin_arm64
+      - linux_386
+      - linux_amd64
+      - linux_arm
+      - linux_arm64
+      - windows_386
+      - windows_amd64
 archives:
   - id: zip
     name_template: "{{ .ProjectName }}_{{ .Os }}_{{ .Arch }}"