Update Netty to 4.1.136 (#7164)

Addresses CVEs in netty-codec-http, netty-codec-http2, and netty-codec
published 2026-07-14. See netty security advisories for details.

Fixes #7162

Author: bhoradc

.changes/next-release/feature-AWSSDKforJavav2-1d04142.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "Update Netty to 4.1.136"
+}

pom.xml

@@ -119,7 +119,7 @@
         <equalsverifier.version>3.15.1</equalsverifier.version>
         <!-- Update netty-open-ssl-version accordingly whenever we update netty version-->
         <!-- https://github.com/netty/netty/blob/4.1/pom.xml search "tcnative.version" -->
-        <netty.version>4.1.135.Final</netty.version>
+        <netty.version>4.1.136.Final</netty.version>
         <unitils.version>3.4.6</unitils.version>
         <xmlunit.version>1.3</xmlunit.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>