Update Netty Version to 4.1.56.Final (#399)

diff --git a/dubbo-samples-async/dubbo-samples-async-onerror/pom.xml b/dubbo-samples-async/dubbo-samples-async-onerror/pom.xml
index 1b63656..3992a82 100644
--- a/dubbo-samples-async/dubbo-samples-async-onerror/pom.xml
+++ b/dubbo-samples-async/dubbo-samples-async-onerror/pom.xml
@@ -67,7 +67,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-all</artifactId>
-                <version>4.1.16.Final</version>
+                <version>4.1.56.Final</version>
             </dependency>
             <dependency>
                 <groupId>org.apache.dubbo</groupId>
diff --git a/dubbo-samples-jetty/pom.xml b/dubbo-samples-jetty/pom.xml
index 210dffb..ff7100a 100644
--- a/dubbo-samples-jetty/pom.xml
+++ b/dubbo-samples-jetty/pom.xml
@@ -69,7 +69,7 @@
       <dependency>
         <groupId>io.netty</groupId>
         <artifactId>netty-all</artifactId>
-        <version>4.1.16.Final</version>
+        <version>4.1.56.Final</version>
       </dependency>
       <dependency>
         <groupId>org.apache.dubbo</groupId>
diff --git a/dubbo-samples-resilience4j/dubbo-samples-resilience4j-filter/pom.xml b/dubbo-samples-resilience4j/dubbo-samples-resilience4j-filter/pom.xml
index 02f5365..a41e2f9 100644
--- a/dubbo-samples-resilience4j/dubbo-samples-resilience4j-filter/pom.xml
+++ b/dubbo-samples-resilience4j/dubbo-samples-resilience4j-filter/pom.xml
@@ -68,7 +68,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-all</artifactId>
-                <version>4.1.16.Final</version>
+                <version>4.1.56.Final</version>
             </dependency>
             <dependency>
                 <groupId>org.apache.dubbo</groupId>
diff --git a/dubbo-samples-resilience4j/dubbo-samples-resilience4j-springboot2/pom.xml b/dubbo-samples-resilience4j/dubbo-samples-resilience4j-springboot2/pom.xml
index a0f2e7e..db71ab4 100644
--- a/dubbo-samples-resilience4j/dubbo-samples-resilience4j-springboot2/pom.xml
+++ b/dubbo-samples-resilience4j/dubbo-samples-resilience4j-springboot2/pom.xml
@@ -69,7 +69,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-all</artifactId>
-                <version>4.1.16.Final</version>
+                <version>4.1.56.Final</version>
             </dependency>
             <dependency>
                 <groupId>org.apache.dubbo</groupId>
diff --git a/dubbo-samples-scala/pom.xml b/dubbo-samples-scala/pom.xml
index 27acb6a..e6103b0 100644
--- a/dubbo-samples-scala/pom.xml
+++ b/dubbo-samples-scala/pom.xml
@@ -47,7 +47,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-all</artifactId>
-                <version>4.1.16.Final</version>
+                <version>4.1.56.Final</version>
             </dependency>
             <dependency>
                 <groupId>org.apache.dubbo</groupId>
diff --git a/dubbo-samples-ssl/pom.xml b/dubbo-samples-ssl/pom.xml
index be45fc7..8fd4305 100644
--- a/dubbo-samples-ssl/pom.xml
+++ b/dubbo-samples-ssl/pom.xml
@@ -59,7 +59,7 @@
             <dependency>
                 <groupId>io.netty</groupId>
                 <artifactId>netty-all</artifactId>
-                <version>4.1.36.Final</version>
+                <version>4.1.56.Final</version>
             </dependency>
 
             <dependency>