util/rand: replace all non crypto rand stuff with own rand package

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

util/jitter/jitter.go

@@ -2,16 +2,14 @@
 package jitter
 
 import (
-	"math/rand"
 	"time"
-)
 
-var (
-	r = rand.New(rand.NewSource(time.Now().UnixNano()))
+	"github.com/unistack-org/micro/v3/util/rand"
 )
 
 // Do returns a random time to jitter with max cap specified
 func Do(d time.Duration) time.Duration {
-	v := r.Float64() * float64(d.Nanoseconds())
+	var rng rand.Rand
+	v := rng.Float64() * float64(d.Nanoseconds())
 	return time.Duration(v)
 }