Correct URL for calendar

Thanks to https://toot.cat/@vivia/112693817496792967

Author: mxsasha

docs/index.md

@@ -82,7 +82,7 @@ Additional resources with many more great pointers:
 - Basic bathroom supplies are much harder to find in an unknown country and area. At DUTH 2015 and [DjangoCon Europe 2016](https://archive.is/8sG1n) there were boxes near the bathrooms with items like toothbrushes and hygiene products, free to take as needed by all attendees. It makes people feel more welcome, and provides a lot of benefit for little effort. If you're able to provide people with over-the-counter drugs like painkillers, that's great too. However, don't place those in publicly accessible boxes, in case children get to them. You can post a note that they're available at your registration desk.
 - The city where you’re holding your conference is probably well known to you. This is not the case for most of your visitors. Help your attendees find their way around by writing something about travelling to and around the conference. [Here’s what I wrote for Django Under the Hood](http://2016.djangounderthehood.com/travel/). Which airport should people go to? How do they best get to the city? How do they get from hotels to the venue? Can I buy transit tickets with a credit card? Do I need a visa? Is there a nearby supermarket?
 - Check local news for local events, construction sites or weather warnings that might impact the attendees' travel to the venue. Communicate these to your attendees to help them navigate it.
-- When picking a date for your event, check a calendar such as [interfaithcalendar.org](http://www.interfaithcalendar.org/) to be aware of any cultural or religious holidays that may be outside of your direct awareness.
+- When picking a date for your event, check a calendar such as [this interfaith calendar](https://interfaithaction.org/contact/calendar/) to be aware of any cultural or religious holidays that may be outside of your direct awareness.
 - Set up a place for your attendees to connect, like Slack. Make it specific to one edition of your conference, so that you can remove it some time after. It's not a great idea to keep it running, because you stay responsible for Code of Conduct incidents.
 - Help attendees stay near other attendees. As soon as you know, tell people what the speaker hotel will be, so that others can decide to book there as well. Publish a few recommendations of alternatives, ideally with varying budgets.
 - In your program, be clear on what food you’re providing. Some conferences offer breakfast at the venue and then forget to tell attendees, which will then already have paid for hotel breakfast. The other way around also happens.