parse +-hhmm timzones

frontend/src/metabase/lib/time.js

 import moment from "moment";
 
-// only attempt to parse the timezone if we're sure we have one (either Z or ±hh:mm)
+// only attempt to parse the timezone if we're sure we have one (either Z or ±hh:mm or +-hhmm)
 // moment normally interprets the DD in YYYY-MM-DD as an offset :-/
 export function parseTimestamp(value, unit) {
     if (moment.isMoment(value)) {
         return value;
-    } else if (typeof value === "string" && /(Z|[+-]\d\d:\d\d)$/.test(value)) {
+    } else if (typeof value === "string" && /(Z|[+-]\d\d:?\d\d)$/.test(value)) {
         return moment.parseZone(value);
     } else if (unit === "year") {
         // workaround for https://github.com/metabase/metabase/issues/1992