Update vendor

vendor/github.com/GeertJohan/go.rice/rice/util.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"math/rand"
+	"time"
+)
+
+// randomString generates a pseudo-random alpha-numeric string with given length.
+func randomString(length int) string {
+	rand.Seed(time.Now().UnixNano())
+	k := make([]rune, length)
+	for i := 0; i < length; i++ {
+		c := rand.Intn(35)
+		if c < 10 {
+			c += 48 // numbers (0-9) (0+48 == 48 == '0', 9+48 == 57 == '9')
+		} else {
+			c += 87 // lower case alphabets (a-z) (10+87 == 97 == 'a', 35+87 == 122 = 'z')
+		}
+		k[i] = rune(c)
+	}
+	return string(k)
+}