Fix for #21
Fix for #21

- Activity listing endpoint no longer appears to work: switched from https://connect.garmin.com/proxy/activity-search-service-1.2/json/activities to https://connect.garmin.com/modern/proxy/activitylist-service/activities/search/activities.

- Activity details json endpoint no longer appears to work: switched from https://connect.garmin.com/modern/proxy/activity-service-1.3/json/activity_embed/<id> to https://connect.garmin.com/modern/proxy/activity-service/activity/<id>.

petergardfjall/garminexport