Add date-ical

[xalgorithm]

Adding the iCal module.

[greg-1-anderson]

When you add an item to composer.json, please also commit the composer.lock file. If you use composer require ... to add the module, then composer.lock should automatically be updated. If you manually edit composer.json, run composer update to update the lock file.

UPDATE: I accidentally said composer install to update the lock file. That's not right; composer update is needed. composer install always keeps the exact versions already in the lock file.

[greg-1-anderson]

You may merge this after you update and commit composer.lock.