Update excessive-capabilities.md

[disconnect3d]

Hi, I would like to ask you to credit the Trail of Bits' "Understanding Docker container escapes" blog post I have written in the past in the CAP_SYS_ADMIN section on the excessive-capabilities.md page about containers. This page contains literal excerpts from my blog post, or, excerpts that are very little changed, which could be thought as plagiarism.

The contents should be either credited as suggested in this pull request, or, the excerpts taken from the blog post should be quoted properly.