Update ghcr.io/cloudnative-pg/postgresql Docker tag to v18

.gitea/workflows/lint-test.yaml

@@ -129,7 +129,6 @@ jobs:
 
             for path in $GIT_DIFF; do
               CHANGED_CHARTS+=$(echo "$path" | awk -F '/' '{print $2}')
-              RENDER_DIR+=$(echo " ")
             done
 
           else
@@ -141,13 +140,13 @@ jobs:
           if [ -n "${CHANGED_CHARTS}" ]; then
             echo ""
             echo ">> Chart to Lint:"
-            echo "$(echo "${CHANGED_CHARTS}" | sort -u)"
+            echo "$(echo "${CHANGED_CHARTS[@]}" | sort -u)"
 
             echo "----"
 
             echo "changes-detected=true" >> $GITEA_OUTPUT
             echo "chart-dir<<EOF" >> $GITEA_OUTPUT
-            echo "$(echo "${CHANGED_CHARTS}" | sort -u)" >> $GITEA_OUTPUT
+            echo "$(echo "${CHANGED_CHARTS[@]}" | sort -u)" >> $GITEA_OUTPUT
             echo "EOF" >> $GITEA_OUTPUT
           else
             echo "changes-detected=false" >> $GITEA_OUTPUT