update example and readme

Author: amyangfei

README.md

@@ -40,7 +40,7 @@ To acquire a lock:
 import "github.com/amyangfei/redlock-go/v2/redlock"
 
 ctx := context.Background()
-expirity, err := lockMgr.Lock(ctx, "resource_name", 200)
+expirity, err := lockMgr.Lock(ctx, "resource_name", 200*time.Milliseconds)
 ```
 
 Where the resource name is an unique identifier of what you are trying to lock and 200 is the number of milliseconds for the validity time.

_examples/basic.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/amyangfei/redlock-go/v2/redlock"
 )
@@ -19,11 +20,11 @@ func main() {
 	}
 
 	ctx := context.Background()
-	expiry, err := lock.Lock(ctx, "foo", 200)
+	expiry, err := lock.Lock(ctx, "foo", 200*time.Millisecond)
 	if err != nil {
 		fmt.Println(err)
 	} else {
-		fmt.Printf("got lock, with expiry %d ms\n", expiry)
+		fmt.Printf("got lock, with expiry %s\n", expiry)
 	}
 	defer lock.UnLock(ctx, "foo")
 }

_examples/counter.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/amyangfei/redlock-go/v2/redlock"
 )
@@ -28,7 +29,7 @@ func writer(count int, back chan string) {
 
 	incr := 0
 	for i := 0; i < count; i++ {
-		expiry, err := lock.Lock(ctx, "foo", 1000)
+		expiry, err := lock.Lock(ctx, "foo", 1000*time.Millisecond)
 		if err != nil {
 			fmt.Println(err)
 		} else {