fix: bump Firefox manifest to 1.6.2 (was missed)

Author: vveerrgg

distros/nostrkey-firefox-v1.6.2.zip

@@ -3,7 +3,7 @@
     "default_locale": "en",
     "name": "__MSG_extension_name__",
     "description": "__MSG_extension_description__",
-    "version": "1.6.1",
+    "version": "1.6.2",
     "short_name": "NostrKey",
     "author": "Humanjava Enterprises Inc",
     "homepage_url": "https://nostrkey.com",