Added credits for Russian localization to README.md
Added credits for Russian localization to README.md

lijie121210/RMDateSelectionViewController,sproutsocial/RMDateSelectionViewController,robertibiris/RMDateSelectionViewController,kevin-hirsch/RMDateSelectionViewController,CooperRS/RMDateSelectionViewController,nickoneill/RMDateSelectionViewController,jiamaozheng/RMDateSelectionViewController,i-miss-you/RMDateSelectionViewController,sproutsocial/RMDateSelectionViewController,zilaiyedaren/RMDateSelectionViewController,scottphc/RMDateSelectionViewController,CooperRS/RMDateSelectionViewController,sandyway/RMDateSelectionViewController,AlexanderMazaletskiy/RMDateSelectionViewController