update: add firefox version v139.0 (#2368)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

firefox.sls

@@ -13,6 +13,7 @@
 
 {% load_yaml as versions -%}
 # renovate: datasource=custom.firefox depName=firefox packageName=LATEST_FIREFOX_VERSION
+- '139.0'
 - '138.0.4'
 - '138.0.3'
 - '138.0.1'