By Aleksandar Vasovic KYIV (Reuters) – Ukrainians raised national flags and played the country’s anthem on Wednesday to show unity against fears of a Russian invasion that Western powers have said could be imminent. The yellow and blue banner fluttered outside schools, hospitals and many shops to mark “Unity Day,” a holiday President Volodymyr Zelenskiy created this week after Russia massed troops near Ukraine’s borders. Russia has denied it will invade, but has warned it could take unspecified “military-technical” action if its security demands, including restrictions on NATO, are not met. On…