Update v3.3 release notes with native packaging info

The native packages (Docker) have updates worth mentioning
on the release notes.

Bug: Issue 13624
Change-Id: I869b604a57fe4a29e8cc8f1dcd12f27e92cf9759
diff --git a/pages/site/releases/3.3.md b/pages/site/releases/3.3.md
index 49b4ed1..f09cca1 100644
--- a/pages/site/releases/3.3.md
+++ b/pages/site/releases/3.3.md
@@ -59,6 +59,13 @@
 
 ## Native packaging
 
+* Allow to use init as a param in docker run
+
+  This allows to easily run the Gerrit image with the `init` argument to explicitly
+  re-run the initialization on an existing or new site.
+
+* CentOS docker image upgrade to v8.2.2004
+
 ## New features
 
 * [Attention Set](http://gerrit-documentation.storage.googleapis.com/Documentation/3.3.0/user-attention-set.html):