Update versions for Zulip Server 3.1.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

Dockerfile

@@ -28,7 +28,7 @@ WORKDIR /home/zulip
 # You can specify these in docker-compose.yml or with
 #   docker build --build-args "ZULIP_GIT_REF=git_branch_name" .
 ARG ZULIP_GIT_URL=https://github.com/zulip/zulip.git
-ARG ZULIP_GIT_REF=3.0
+ARG ZULIP_GIT_REF=3.1
 
 RUN git clone "$ZULIP_GIT_URL" && \
     cd zulip && \

README.md

@@ -6,10 +6,10 @@ This is a container image for running [Zulip](https://zulip.com)
 ([GitHub](https://github.com/zulip/zulip)) in
 [production][prod-overview]. Image available from:
 
-* [**Docker Hub**](https://hub.docker.com/r/zulip/docker-zulip) (`docker pull zulip/docker-zulip:3.0-0`)
+* [**Docker Hub**](https://hub.docker.com/r/zulip/docker-zulip) (`docker pull zulip/docker-zulip:3.1-0`)
 
-Current Zulip version: `3.0`
-Current Docker image version: `3.0-0`
+Current Zulip version: `3.1`
+Current Docker image version: `3.1-0`
 
 Project status: **Alpha**.  While this project works and is
 used by many sites in production, configuring is substantially more

docker-compose.yml

@@ -48,13 +48,13 @@ services:
     volumes:
       - '/opt/docker/zulip/redis:/data:rw'
   zulip:
-    image: 'zulip/docker-zulip:3.0-0'
+    image: 'zulip/docker-zulip:3.1-0'
     build:
       context: .
       args:
         # Change these if you want to build zulip from a different repo/branch
         ZULIP_GIT_URL: https://github.com/zulip/zulip.git
-        ZULIP_GIT_REF: 3.0
+        ZULIP_GIT_REF: 3.1
         # Set this up if you plan to use your own CA certificate bundle for building
         # CUSTOM_CA_CERTIFICATES:
     ports:

kubernetes/zulip-rc.yml

@@ -62,7 +62,7 @@ spec:
           - name: postgresql-persistent-storage
             mountPath: /var/lib/postgresql
       - name: zulip
-        image: zulip/docker-zulip:3.0-0
+        image: zulip/docker-zulip:3.1-0
         resources:
           limits:
             cpu: 100m