Change edition selection to a dropdown

Soon it will have 3 values

Author: shepmaster

tests/spec/features/editions_spec.rb

@@ -11,7 +11,7 @@
   end
 
   scenario "using the 2015 edition" do
-    in_advanced_options_menu { choose '2015' }
+    in_advanced_options_menu { select '2015' }
     click_on("Run")
 
     within(:output, :stderr) do
@@ -21,7 +21,7 @@
   end
 
   scenario "using the 2018 edition" do
-    in_advanced_options_menu { choose '2018' }
+    in_advanced_options_menu { select '2018' }
     click_on("Run")
 
     within(:output, :stderr) do

tests/spec/features/sharing_with_others_spec.rb

@@ -14,7 +14,7 @@
 
     in_channel_menu { click_on("Nightly") }
     in_mode_menu { click_on("Release") }
-    in_advanced_options_menu { choose("2018") }
+    in_advanced_options_menu { select("2018") }
 
     within(:header) { click_on 'Share' }
 

tests/spec/features/url_parameters_spec.rb

@@ -26,7 +26,7 @@
   RSpec::Matchers.define :have_edition do |expected|
     match do |actual|
       in_advanced_options_menu do
-        expect(page).to have_checked_field(expected, visible: false)
+        expect(page).to have_select(selected: expected)
       end
     end
   end

ui/frontend/AdvancedOptionsMenu.tsx

@@ -2,7 +2,7 @@ import React, { useCallback } from 'react';
 import { useSelector, useDispatch } from 'react-redux';
 
 import * as actions from './actions';
-import { Either as EitherConfig } from './ConfigElement';
+import { Either as EitherConfig, Select as SelectConfig } from './ConfigElement';
 import MenuGroup from './MenuGroup';
 import { State } from './reducers';
 import * as selectors from './selectors';
@@ -21,14 +21,15 @@ const AdvancedOptionsMenu: React.SFC = () => {
 
   return (
     <MenuGroup title="Advanced options">
-      <EitherConfig
-        id="edition"
+      <SelectConfig
         name="Edition"
-        a={Edition.Rust2015}
-        b={Edition.Rust2018}
         value={edition}
         isNotDefault={isEditionSet}
-        onChange={changeEdition} />
+        onChange={changeEdition}
+      >
+        <option value={Edition.Rust2015}>2015</option>
+        <option value={Edition.Rust2018}>2018</option>
+      </SelectConfig>
 
       <EitherConfig
         id="backtrace"