Version bump for Crashlytics. (#4792)

FirebaseCrashlytics.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'FirebaseCrashlytics'
-  s.version          = '4.0.0-beta.2'
+  s.version          = '4.0.0-beta.3'
   s.summary          = 'Best and lightest-weight crash reporting for mobile, desktop and tvOS.'
   s.description      = 'Firebase Crashlytics helps you track, prioritize, and fix stability issues that erode app quality.'
   s.homepage         = 'https://firebase.google.com/'