update installation guide
update installation guide

alessandrots/cordova-plugin-datepicker,gemini612/cordova-plugin-datepicker,aabluedragon/cordova-plugin-datepicker,thiphariel/cordova-plugin-datepicker,jackuse/cordova-plugin-datepicker,bluebile/cordova-plugin-datepicker,bluebile/cordova-plugin-datepicker,jackuse/cordova-plugin-datepicker,jeroenv/cordova-plugin-datepicker,roberthovhannisyan/cordova-plugin-datepicker,gemini612/cordova-plugin-datepicker,alessandrots/cordova-plugin-datepicker,web-slinger/cordova-plugin-datepicker,aabluedragon/cordova-plugin-datepicker,jeroenv/cordova-plugin-datepicker,web-slinger/cordova-plugin-datepicker,smadey/cordova-plugin-datepicker,ErwanLP/cordova-plugin-datepicker,AgrawalRahul/cordova-plugin-datepicker,smadey/cordova-plugin-datepicker,VitaliiBlagodir/cordova-plugin-datepicker,joewoodhouse/cordova-plugin-datepicker,jackuse/cordova-plugin-datepicker,bluebile/cordova-plugin-datepicker,ErwanLP/cordova-plugin-datepicker,roberthovhannisyan/cordova-plugin-datepicker,VitaliiBlagodir/cordova-plugin-datepicker,thiphariel/cordova-plugin-datepicker,AgrawalRahul/cordova-plugin-datepicker,joewoodhouse/cordova-plugin-datepicker