Added Support for getting qaurter of the year

src/ReDate_quarter.res

@@ -0,0 +1,9 @@
+let getQuarter = (date: Js.Date.t): int => {
+  let month = Js.Date.getMonth(date)
+  switch month {
+  | _ if month >= 0.0 && month <= 2.0 => 1
+  | _ if month >= 3.0 && month <= 5.0 => 2
+  | _ if month >= 6.0 && month <= 8.0 => 3
+  | _ => 4
+  }
+}