Add security audit doc

Signed-off-by: Doug Davis <dug@microsoft.com>

Author: Doug Davis

README.md

@@ -109,6 +109,10 @@ native ecosystem by making our systems interoperable with CloudEvents.
 If there is a security concern with one of the specifications in this
 repository please [open an issue](https://github.com/cloudevents/spec/issues).
 
+A security assessment was performed by
+[Trail of Bits](https://www.trailofbits.com/) in October 2022. The report
+can be found [here](docs/CE-SecurityAudit-2022-10.pdf).
+
 ### Communications
 
 The main mailing list for e-mail communications:

docs/CE-SecurityAudit-2022-10.pdf

@@ -94,6 +94,8 @@ CloudEvents 是一个以通用格式来描述事件数据的规范。它提供
 
 如果对本仓库中任意规范有安全方面的担忧，请[提交一个issue](https://github.com/cloudevents/spec/issues) ，告知我们。
 
+[Trail of Bits](https://www.trailofbits.com/) 于 2022 年 10 月对本项目进行了安全评估。详情参见[完整报告](../../docs/CE-SecurityAudit-2022-10.pdf)。
+
 ## 联系方式
 
 邮件联系方式如下:
@@ -128,4 +130,4 @@ CloudEvents 规范由
 
 工作组会定期举办与主流会议一致的线下会议。查看
 [会议纪要文档](https://docs.google.com/document/d/1OVF68rpuPK5shIHILK9JOqlZBbfe91RNzQ7u_P7YCDE/edit#)
-了解更多未来会议的计划。
+了解更多未来会议的计划。