Add Version Output Support to Snowflake

From now on, there will be a file at common/version/version.go that includes current version number.

common/utls/client_hello_id_version.go

@@ -0,0 +1,24 @@
+package utls
+
+import (
+	"git.torproject.org/pluggable-transports/snowflake.git/v2/common/version"
+	"strings"
+)
+
+func generateVersionOutput() string {
+	var versionOutputBuilder strings.Builder
+
+	versionOutputBuilder.WriteString(`Known utls-imitate values:
+(empty)
+`)
+
+	for _, name := range ListAllNames() {
+		versionOutputBuilder.WriteString(name)
+		versionOutputBuilder.WriteRune('\n')
+	}
+	return versionOutputBuilder.String()
+}
+
+func init() {
+	version.AddVersionDetail(generateVersionOutput())
+}