Merge branch 'stable-3.0'

* stable-3.0:
  Prevent automatic upgrade of Gerrit package

Change-Id: I3ef1fda2b3e3a929246d0e3ae61b6883c6a38222
diff --git a/centos/7/Dockerfile b/centos/7/Dockerfile
index 735ed4c..09bf078 100644
--- a/centos/7/Dockerfile
+++ b/centos/7/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:7.6.1810
+FROM centos:7.7.1908
 MAINTAINER Gerrit Code Review Community
 
 # Add Gerrit packages repository
@@ -10,7 +10,7 @@
 # (pre-trans Gerrit script needs to have access to the Java command)
 RUN yum -y install initscripts && \
     yum -y install java-1.8.0-openjdk && \
-    yum -y install gerrit-3.0.7-1 && \
+    yum -y install gerrit-3.1.3-1 && \
     /entrypoint.sh init && \
     rm -f /var/gerrit/etc/{ssh,secure}* && rm -Rf /var/gerrit/{static,index,logs,data,index,cache,git,db,tmp}/* && chown -R gerrit:gerrit /var/gerrit && \
     yum -y clean all
diff --git a/ubuntu/18/Dockerfile b/ubuntu/18/Dockerfile
index 55a5c20..f945529 100644
--- a/ubuntu/18/Dockerfile
+++ b/ubuntu/18/Dockerfile
@@ -16,7 +16,7 @@
 # Install OpenJDK and Gerrit in two subsequent transactions
 # (pre-trans Gerrit script needs to have access to the Java command)
 RUN apt-get -y install openjdk-8-jdk
-RUN apt-get -y install gerrit=3.0.7-1 && \
+RUN apt-get -y install gerrit=3.1.3-1 && \
     apt-mark hold gerrit && \
     /entrypoint.sh init && \
     rm -f /var/gerrit/etc/{ssh,secure}* && rm -Rf /var/gerrit/{static,index,logs,data,index,cache,git,db,tmp}/* && chown -R gerrit:gerrit /var/gerrit