make 2021 the default edition

Author: lqd

tests/spec/features/url_parameters_spec.rb

@@ -104,7 +104,7 @@
 
   scenario "loading without code or an edition" do
     visit '/'
-    expect(page).to have_edition('2018')
+    expect(page).to have_edition('2021')
   end
 
   def editor

ui/frontend/reducers/configuration.ts

@@ -42,7 +42,7 @@ const DEFAULT: State = {
   primaryAction: PrimaryActionAuto.Auto,
   channel: Channel.Stable,
   mode: Mode.Debug,
-  edition: Edition.Rust2018,
+  edition: Edition.Rust2021,
   backtrace: Backtrace.Disabled,
 };
 

ui/frontend/selectors/index.ts

@@ -122,7 +122,7 @@ export const getChannelLabel = (state: State) => {
 
 export const isEditionDefault = createSelector(
   editionSelector,
-  edition => edition == Edition.Rust2018,
+  edition => edition == Edition.Rust2021,
 );
 
 export const getBacktraceSet = (state: State) => (