MAINTAINERS: add Patrick Williams

Large portions of the codebase were originally written by me
before maintainers existed.  I am returning to the project and
plan to do significant enhancements and cleanups to sdbusplus.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I3ac6f6597c78041785ded272d1e6ce8974d5b49a
diff --git a/MAINTAINERS b/MAINTAINERS
index d648b8b..7282274 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -42,6 +42,7 @@
 START OF MAINTAINERS LIST
 -------------------------
 
+M:  Patrick Williams <patrick@stwcx.xyz> <stwcx!>
 M:  William Kennington <wak@google.com> <wak-work!>
 M:  Vernon Mauery <vernon.mauery@linux.intel.com> <vmauery!>
 M:  Lei Yu <mine260309@gmail.com> <LeiYU!>