chore: update schedule table with all upcoming events

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: AndreaGriffiths11

README.md

@@ -19,4 +19,5 @@ Don't miss this chance to explore the world of Open Source every Friday. We're l
 | June 12, 2026 | [Joseph Katsioloudes](https://github.com/githubevents/open-source-friday/issues/219) | Secure Code Game | TBD |
 | June 15, 2026 | [Ayushman Bhattacharya](https://github.com/githubevents/open-source-friday/issues/223) | OreoOS | TBD |
 | June 19, 2026 | [Angela Wen](https://github.com/githubevents/open-source-friday/issues/222) | TBD | Andrea Griffiths |
+| October 2, 2026 | [Christopher W. Blake](https://github.com/githubevents/open-source-friday/issues/221) | Open Proficiency Model | TBD |
 <!-- SCHEDULE_END -->