fix(build): backslash-escape "/" in character class to satisfy minimizers (#4206) r=vladikoff
fix(build): backslash-escape "/" in character class to satisfy minimizers (#4206) r=vladikoff


shane-tomlinson/fxa-content-server,mozilla/fxa-content-server,shane-tomlinson/fxa-content-server,shane-tomlinson/fxa-content-server,mozilla/fxa-content-server,mozilla/fxa-content-server