Highlight uncommitted changes in version

If there are uncommitted changes in the app repository when building,
then append `_uncommitted_<random>` to it to distinguish the image
from one built from a clean checkout.

Also change the version used when renaming a container on redeploy to
distinguish and explain the version suffixes.

test/integration/docker/deployer/app/Dockerfile

@@ -1,4 +1,7 @@
 FROM nginx:1-alpine-slim
 
 COPY default.conf /etc/nginx/conf.d/default.conf
-COPY version /usr/share/nginx/html/version
+
+ARG COMMIT_SHA
+RUN echo $COMMIT_SHA > /usr/share/nginx/html/version
+

test/integration/docker/deployer/app/config/deploy.yml

@@ -9,6 +9,8 @@ registry:
   password: root
 builder:
   multiarch: false
+  args:
+    COMMIT_SHA: <%= `git rev-parse HEAD` %>
 healthcheck:
   cmd: wget -qO- http://localhost > /dev/null
 traefik: