QATAPP-18528: Update README.md for Async Mode Nginx 0.4.1.

Update OPENSSL & QAT Engine version to readme. aaa
Add QAT Engine multibuffer to readme as new feature.
Add instruction of generate & apply Async Nginx patch.
Add early data failure with HKDF offload as known issue.
Add reload failure with QAT Engine conf removed as known issue.

README.md

@@ -50,6 +50,8 @@ be found in the file headers of the relevant files.
 * Support OpenSSL Cipher PIPELINE feature
 * Support QATzip module to accelerate GZIP compression with Intel® Quickassist Technology
 * Support software fallback for asymmetric cryptography algorithms.
+* Support [QAT Engine multibuffer feature][10]
+[10]:https://github.com/intel/QAT_Engine#intel-qat-openssl-engine-multibuffer-support
 
 ## Hardware Requirements
 
@@ -69,13 +71,31 @@ This release was validated on the following:
 
 * Async Mode Nginx has been tested with the latest Intel® QuickAssist Acceleration Driver.
 Please download the QAT driver from the link https://01.org/intel-quickassist-technology
-* OpenSSL-1.1.1c
-* QAT engine v0.5.42
+* OpenSSL-1.1.1g
+* QAT engine v0.5.44
 * QATzip v1.0.1
 
 ## Additional Information
 
 * Async Mode Nginx is developed based on Nginx-1.16.1.
+
+* Generate Async Mode Nginx patch against official Nginx-1.16.1.
+
+```bash
+  git clone https://github.com/intel/asynch_mode_nginx.git
+  wget http://nginx.org/download/nginx-1.16.1.tar.gz
+  tar -xvzf ./nginx-1.16.1.tar.gz
+  diff -Naru -x .git nginx-1.16.1 asynch_mode_nginx > async_mode_nginx_1.16.1.patch
+```
+
+* Apply Async Mode Nginx patch to official Nginx-1.16.1.
+
+```bash
+  wget http://nginx.org/download/nginx-1.16.1.tar.gz
+  tar -xvzf ./nginx-1.16.1.tar.gz
+  patch -p0 < async_mode_nginx_1.16.1.patch
+```
+
 * Async Mode Nginx SSL engine framework provides new directives:
 
 **Directives**
@@ -570,6 +590,15 @@ This is a sample configure file shows how to configure QAT in nginx.conf. This f
    memory and hard disk space. Disk space exhausted or out of memory would cause core dump when
    nginx receives HUP signal during handshake phase.
 
+**TLS1.3 Early data function may failed when enable HKDF offload in QAT Engine**<br/>
+   When enable HKDF offload in QAT Engine, and enable early data function with TLS1.3 protocol in
+   Nginx configuration, early data operation in session reuse case may failed.
+
+**Core-dump happened when reload nginx worker with ssl_engine removed from nginx.conf**<br/>
+   Start Async Mode Nginx with ssl_engine directive in nginx.conf, then remove the ssl_engine
+   directive and reload Async Mode Nginx with command `nginx -s reload`, will cause coredump.
+   Need to avoid this kind of operation currently.
+
 ## Intended Audience
 
 The target audience may be software developers, test and validation engineers,