chore: Updated to firefox 139.0, b=(no-bug), c=no-component

Author: mr-cheffy

README.md

@@ -29,7 +29,7 @@
 
 ## 🖥️ Compatibility
 
-Zen is currently built using Firefox version `138.0.4`! 🚀
+Zen is currently built using Firefox version `139.0`! 🚀
 
 - [`Zen Twilight`](https://zen-browser.app/download?twilight) - Is currently built using Firefox version `RC 139.0`!
 - Check out the latest [release notes](https://zen-browser.app/release-notes)!

build/firefox-cache/l10n-last-commit-hash

@@ -1 +1 @@
-82a08ea3ce2d17f21f3d45f4b5607a37590b0158
+da30619f3ea895b356ded705b8dff9e4f271198f

surfer.json

@@ -5,7 +5,7 @@
   "binaryName": "zen",
   "version": {
     "product": "firefox",
-    "version": "138.0.4",
+    "version": "139.0",
     "candidate": "139.0"
   },
   "buildOptions": {
@@ -19,7 +19,7 @@
       "brandShortName": "Zen",
       "brandFullName": "Zen Browser",
       "release": {
-        "displayVersion": "1.12.8b",
+        "displayVersion": "1.12.9b",
         "github": {
           "repo": "zen-browser/desktop"
         },