config: add filter "meshtastic-firmware-config" (for masking some sensitive values)

gitconfig

@@ -71,6 +71,9 @@
 	process = git-lfs filter-process
 	required = true
 
+[filter "meshtastic-firmware-config"]
+    clean = "yq --yaml-output --indentless-lists '.channel_url = \"…\" | .config.bluetooth.fixedPin = \"…\" | .module_config.ambientLighting.blue = \"…\" | .module_config.ambientLighting.green = \"…\" | .module_config.ambientLighting.red = \"…\"' --"
+
 [commit]
 	gpgsign = true
 	verbose = true