update vendor and use single static

vendor/github.com/gin-gonic/autotls/example/example2.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"log"
+
+	"github.com/gin-gonic/autotls"
+	"github.com/gin-gonic/gin"
+	"golang.org/x/crypto/acme/autocert"
+)
+
+func main() {
+	r := gin.Default()
+
+	// Ping handler
+	r.GET("/ping", func(c *gin.Context) {
+		c.String(200, "pong")
+	})
+
+	m := autocert.Manager{
+		Prompt:     autocert.AcceptTOS,
+		HostPolicy: autocert.HostWhitelist("example1.com", "example2.com"),
+		Cache:      autocert.DirCache("/var/www/.cache"),
+	}
+
+	log.Fatal(autotls.RunWithManager(r, &m))
+}