Update firefox extension

diff --git a/firefox b/firefox
index 42acd8d..f76b13b 160000 (submodule)
--- a/firefox
+++ b/firefox
@@ -1 +1 @@
-Subproject commit 42acd8de6fb34f7c8d0c75dba435675f1b29e9d7
+Subproject commit f76b13baadd325324178a7a6a9c45b157186c08e