updated android screenshots in README.md
updated android screenshots in README.md

icefoggy/HackerNews-React-Native,xuan9/HackerNews-React-Native,iSimar/HackerNews-React-Native,exponentjs/HackerNews-React-Native,ivanph/HackerNews-React-Native,xuan9/HackerNews-React-Native,ivanph/HackerNews-React-Native,icefoggy/HackerNews-React-Native,iSimar/HackerNews-React-Native,exponentjs/HackerNews-React-Native