fix REAME.md war file name
fix REAME.md war file name

https://github.com/dlecan/play2-war-plugin/blob/d8a3f50ab789c/project-code/plugin/src/main/scala/Play2WarCommands.scala#L57
matterche/play2-war-plugin,matterche/play2-war-plugin,swatikiran123/play2-war-plugin,swatikiran123/play2-war-plugin