Add the ability to add the ember days to your calendar by building an ics file. Perhaps with https://www.npmjs.com/package/ics

When you click the "Add to Calendar" button it should

• build the ics file
• download the ics file

Upgrade to Vue 3
https://v3.vuejs.org/guide/migration/introduction.html#overview

Ember days were calculated to start Wednesday Sept 14 but should begin Wednesday Sept 21.

This year (2015) the Ember Days do not fall this week right after the Feast of the Holy Cross, but the next week. In 1960 under Pope St. John XXIII, the rules for establishing the dates for Ember Days changed, and connected the Ember Days to follow the Third Sunday of September, which will be September 21, 23 and 24, 2015. The changes corresponded to following the Divine Office or Breviary.

More info

Add the major and minor rogation days to the list and calendar (#2)

Major: Apr 25
Minor: 3 days leading up to Ascension Thursday
https://www.catholic.com/encyclopedia/rogation-days