CI: Only publish as an Alpha Build

I no longer wish to publish apks in the beta channel as many users leave
reviews on this beta channel, which do not show up on the app's reviews
page.

.circleci/config.yml

@@ -33,5 +33,5 @@ jobs:
           name: Upload Crashlytics Symbols
           command: ./scripts/android_crashlytics.sh
       - run:
-          name: Publish Beta
-          command: cd android && fastlane betaBuild
+          name: Publish Alpha
+          command: cd android && fastlane alphaBuild

android/fastlane/Fastfile

@@ -2,7 +2,7 @@ default_platform(:android)
 
 platform :android do
   desc "Publish a new Android APK"
-  lane :betaBuild do
+  lane :alphaBuild do
     # Return the number of commits in current git branch
     # build_number = number_of_commits()
     # Dir.chdir "../../" do
@@ -11,7 +11,7 @@ platform :android do
     #  sh("flutter", "build", "apk", "--build-number=#{build_number}")
     # end
 
-    upload_to_play_store(track: "beta",
+    upload_to_play_store(track: "alpha",
       aab: "../build/app/outputs/bundle/release/app.aab",
       skip_upload_metadata: true,
       skip_upload_images: true,