Update to gitea 1.17.3

This updates our gitea images from 1.17.2 to 1.17.3. Git diff of the
three template files we override between 1.17.2 and 1.17.3 show no
changes to the templates. Also, while the changelog indicates go 1.19
fmt is used with gitea 1.17 now the 1.17 Dockerfile continues to build
gitea itself with go 1.18. We don't update our golang version for this
reason.

The changelog can be found here:
  https://github.com/go-gitea/gitea/blob/v1.17.3/CHANGELOG.md

Additionally, I've modified how we do our docker image prune step to
keep old images for 3 days. The reason for this is it gives us a short
window of time where we can easily revert to the old image that we have
stored locally on the system. Keep in mind that this will slightly
increase disk consumption on the nodes by about 1GB per
gitea+gitea-ssh+mariadb set. I think this is worthwhile considering
these images don't update often so we should only ever have one extra
old set on the node. If others don't care for this feel free to modify
the change to remove this edit.

Change-Id: I84e89e461ae8957c553c8f3d1b537af622a824b4

docker/gitea/Dockerfile

@@ -27,7 +27,7 @@ FROM docker.io/library/golang:1.18-bullseye AS build-env
 
 LABEL maintainer="infra-root@openstack.org"
 
-ARG GITEA_VERSION="v1.17.2"
+ARG GITEA_VERSION="v1.17.3"
 ENV TAGS "bindata $TAGS"
 
 #Build deps

playbooks/roles/gitea/tasks/main.yaml

@@ -70,7 +70,10 @@
         chdir: /etc/gitea-docker/
     - name: Run docker prune to cleanup unneeded images
       shell:
-        cmd: docker image prune -f
+        # Keep images around for 3 days before pruning them. Allows for
+        # easy rollback if necessary. Note "3d" seems to be rejected by
+        # docker but 72 hours == 3 days.
+        cmd: docker image prune -f --filter "until=72h"
 
 # User management outside of service bringup to avoid confusion between
 # the two stages.