Find latest version tag which exists on domjudge.org

We can't use latest as there is no release on domjudge.org with that
name, but this makes atleast clear which index we try to get.

This reverts commit 43982ab and
improves on it.

Author: vmcj

.github/workflows/build-domjudge-container-PR.yml

@@ -49,7 +49,7 @@ jobs:
           sudo apt update; sudo apt install -y jq curl
           set -x
             HUBURL="https://registry.hub.docker.com/v2/repositories/domjudge/domserver/tags"
-            TAG=$(curl $HUBURL|jq '.results | sort_by(.name) | last.name')
+            TAG=$(curl $HUBURL|jq '.results | sort_by(.name) | .[-2].name')
             DJ_TAG=${TAG//\"}
           set +x
           echo "DOMJUDGE_VERSION=$DJ_TAG" >> $GITHUB_ENV

.github/workflows/build-domjudge-container-release.yml

@@ -41,7 +41,7 @@ jobs:
           sudo apt update; sudo apt install jq curl -y
           set -x
             HUBURL="https://registry.hub.docker.com/v2/repositories/domjudge/domserver/tags"
-            TAG=$(curl $HUBURL|jq '.results | sort_by(.name) | last.name')
+            TAG=$(curl $HUBURL|jq '.results | sort_by(.name) | .[-2].name')
             DJ_TAG=${TAG//\"}
           set +x
           echo "DOMJUDGE_VERSION=$DJ_TAG" >> $GITHUB_ENV