v3.18.0

• Fix Add-ons field not appearing on pledge screen (#1937) (79df3bf)
• update internal/external version code (ec494ff)
• bump build version code (2e403b4)
• update internal/external version code from previous build (a6bbae7)
• update version names (b413013)
• Add post campaign feature flag (#1934) (b636095)
• MBL-808: BackingFragmentViewModel.kt to Jetpack ViewModel and RxJava2.2 (#1931) (5a328e3)
• MBL-905: Remove Use of IA tab feature flag (#1932) (30e9684)
• Update NotificationActivity to RX2 (#1933) (fe81cd6)
• [MBL-1135] Add analytics value for session_force_dark_mode (#1930) (6c857bd)
• Update RepliesStatusCellViewHolderViewmodel to RX2 (#1928) (a20e8f9)
• MBL-807: ActivityFeed migrated to RXJava2 (#1929) (d5ce29a)
• update viewholder viewmodel to rx2 (#1927) (ac0203c)
• [MBL-1127] Dark mode (#1922) (41fc5b9)
• MBL-810: DeeplinkViewModel.kt to Jetpack ViewModel and RxJava2.2 (#1924) (97e6b10)
• update errored backing view model to rx2 (#1926) (62ce953)
• MBL-1077: Coroutines in ChangePasswordViewModel + Tests (#1923) (8045fef)
• remove unneeded viewmodel (#1925) (69c7220)
• MBL-779: ShippingRuleViewHolder migrated to RXJava2 (#1921) (10a75aa)
• • Android Studio Hedgehog (#1920) (698195a)
• MBL-1053: Identify if https links in messages are KSR links (#1917) (d09017f)
• [MBL-797] Update root comment viewholder to rx2 (#1918) (f478b47)
• • upgraded machine version, installing firebase CLI was erroring due to an old version of node, this new machine has newer node version. (#1916) (303cad2)