update sentinel version to 1.5.1

spring-cloud-alibaba-dependencies/pom.xml

@@ -17,7 +17,7 @@
     <description>Spring Cloud Alibaba Dependencies</description>
 
     <properties>
-        <sentinel.version>1.4.2</sentinel.version>
+        <sentinel.version>1.5.1</sentinel.version>
         <oss.version>3.1.0</oss.version>
         <fescar.version>0.4.0</fescar.version>
         <nacos.client.version>1.0.0-RC3</nacos.client.version>