CouchbaseLiteSwift POD install fails

and BTW, I just tested it with following pod file and works fine

# Uncomment the next line to define a global platform for your project
# platform :ios, '9.0'

target 'CocoapodTest' do
  # Comment the next line if you're not using Swift and don't want to use dynamic frameworks
  use_frameworks!

  # Pods for CocoapodTest
use_frameworks!
  pod 'CouchbaseLiteSwift', :git => 'https://github.com/couchbase/couchbase-lite-ios.git', :tag => '2.0DB021', :submodules => true

end

Output from my install …

pod --verbose install
....
Sending stats
      - CouchbaseLiteSwift, 2.0DB021

-> Pod installation complete! There is 1 dependency from the Podfile and 1 total pod installed.