Bump version to 0.3.2.pre.1 (#254)

Author: lfkellogg

lib/fastlane/plugin/firebase_app_distribution/version.rb

@@ -1,5 +1,5 @@
 module Fastlane
   module FirebaseAppDistribution
-    VERSION = "0.3.1"
+    VERSION = "0.3.2.pre.1"
   end
 end