new: [nextcloud] make ``upgrade`` aware of docker version compatibilities

Some nextcloud versions are not compatible anymore with versions <= 20.10.

nextcloud/actions/upgrade

@@ -120,6 +120,19 @@ for v in "${last_available_versions[@]}"; do
     fi
 done
 
+docker_version=$(docker info --format '{{.ServerVersion}}')
+last_compatible_versions=()
+for v in "${last_upgradable_versions[@]}"; do
+    if version_gt "$docker_version" 20.10.0; then
+        last_compatible_versions+=("$v")
+        continue
+    fi
+    if version_gt "26.99.99" "$v"; then
+        last_compatible_versions+=("$v")
+    fi
+done
+
+
 if [ "${#last_upgradable_versions[@]}" == 0 ]; then
     info "${DARKYELLOW}nextcloud${NORMAL} is already ${GREEN}up-to-date${NORMAL}."
     exit 0
@@ -130,7 +143,7 @@ if [ -z "$target" ]; then
     target=${last_upgradable_versions[0]}
 else
     if [[ " ${last_available_versions[*]} " != *" $target "* ]]; then
-        err "Invalid version $target selected, please specify one of:"
+        err "Invalid version ${WHITE}$target${NORMAL} selected, please specify one of:"
         for v in "${last_upgradable_versions[@]}"; do
             echo " - $v"
         done >&2
@@ -139,6 +152,16 @@ else
     info "Target version ${WHITE}$target${NORMAL}"
 fi
 
+if [[ " ${last_compatible_versions[*]} " != *" $target "* ]]; then
+    err "Sorry, ${DARKYELLOW}$SERVICE_NAME${NORMAL} ${WHITE}$target${NORMAL}" \
+        "require docker version >= ${WHITE}20.10${NORMAL} (current: $docker_version)"
+    echo "  Nextcloud versions <= ${WHITE}27${NORMAL} are still supported." >&2
+    echo "  You can specify one of:" >&2
+    for v in "${last_compatible_versions[@]}"; do
+        echo "   - $v" >&2
+    done
+    exit 1
+fi
 
 upgrade_path=($(echo "${last_upgradable_versions[*]}" | tr ' ' '\n' | uniq -w 3 | sort -V))