Only autobuild for linux, as sqlite needs cgo (#38)

.goreleaser.yml

 builds:
-  - main: main.go
-    binary: acme-dns
+  - binary: acme-dns
     env:
       - CGO_ENABLED=1
     goos:
       - linux
-      - darwin
-      - windows
-      - freebsd
-      - netbsd
-      - openbsd
     goarch:
       - 386
       - amd64
-      - arm
-      - arm64
-    ignore:
-      - goos: darwin
-        goarch: 386
-      - goos: darwin
-        goarch: arm
-      - goos: darwin
-        goarch: arm64
 
 archive:
   format: tar.gz
-  format_overrides:
-    - goos: windows
-      format: zip
-    - goos: darwin
-      format: zip
-  replacements:
-    amd64: 64bit
-    386: 32bit
-    darwin: macOS
   files:
     - LICENSE
     - README.md