Document revert on 3.0.x

Author: thinkernel

README.md

@@ -17,7 +17,7 @@
  * openfrontier/gerrit:latest -> 3.3.2
  * openfrontier/gerrit:3.2.x -> 3.2.7
  * openfrontier/gerrit:3.1.x -> 3.1.12
- * openfrontier/gerrit:3.0.x  -> 3.0.16
+ * openfrontier/gerrit:3.0.x  -> 3.0.15
  * openfrontier/gerrit:2.16.x -> 2.16.26
  * openfrontier/gerrit:2.15.x -> 2.15.18
  * openfrontier/gerrit:2.14.x -> 2.14.20