Add PCD @ Leicester to the PCD map

[github-actions]

Note

The Plus Code was auto-recovered from the user's input (JVMC+RJ7 Leicester) using the city as a reference. Please verify the map pin placement is correct (https://plus.codes/9C4WJVMC+RJ7).

Closes #25

This PR was generated from the "New Event" issue form for PCD @ Leicester.
Submitted by @NewMediaArtClub.

Review checklist:

• Event name "PCD @ Leicester" is correct
• Public name "Sean Carroll" and email "hi@newmediaart.club" are correct
• Short description is left blank — confirm this is intentional
• Long description is left blank — confirm this is intentional
• Date is marked TBD — confirm this is intentional
• Venue address and map pin placement are correct
• Check the map and event details page in the Netlify preview (link posted below by the Netlify bot)

[netlify]

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