chore: read commit from Go

That way we don't rely on an external tool to pass it and it's always
set at build time.

Signed-off-by: Yves Brissaud <yves.brissaud@docker.com>

.goreleaser.yaml

@@ -22,7 +22,6 @@ builds:
       -s
       -extldflags '-static'
       -X github.com/docker/index-cli-plugin/internal.version={{.Version}}
-      -X github.com/docker/index-cli-plugin/internal.commit={{.Commit}}
 
 archives:
   - format: tar.gz

internal/version.go

@@ -22,6 +22,7 @@ package internal
 import (
 	"fmt"
 	"runtime"
+	"runtime/debug"
 )
 
 // build-time arguments
@@ -30,6 +31,16 @@ var (
 	commit  = "n/a"
 )
 
+func init() {
+	if info, ok := debug.ReadBuildInfo(); ok {
+		for _, setting := range info.Settings {
+			if setting.Key == "vcs.revision" {
+				commit = setting.Value
+			}
+		}
+	}
+}
+
 // Version information from build time args and environment
 type Version struct {
 	Version   string