fix: Use correct branch instead of hard-coded one in release script (#804)

Author: Techassi

scripts/publish-new-version.sh

@@ -110,7 +110,7 @@ PLAYBOOK_FILES=("$DOCS_DIRECTORY/antora-playbook.yml" "$DOCS_DIRECTORY/local-ant
 # Loop through each playbook file
 for yaml_file in "${PLAYBOOK_FILES[@]}"; do
     # Update all sources except stackable-cockpit.
-    yq "with(.content.sources.[]; select(.url | test(\".*(stackable-cockpit).*\") | not) | .branches |= .[:1] + [\"release-25.7\"] + .[1:])" -i "$yaml_file"
+    yq "with(.content.sources.[]; select(.url | test(\".*(stackable-cockpit).*\") | not) | .branches |= .[:1] + [\"$BRANCH\"] + .[1:])" -i "$yaml_file"
 done
 
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