Add FOSSCOMM 2024 (#1083)

* Add FOSSCOMM 2024

* Update README.md

---------

Co-authored-by: Aurelie Vache <scraly@gmail.com>

README.md

@@ -578,6 +578,7 @@ All the data (past and coming) are available publicly in JSON:
 * 9: [BSides Sydney 2024](http://bsides.sydney) - Sydney (Australia) <a href="https://www.papercall.io/bsidessyd24"><img alt="CFP BSides Sydney 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2030-June-2024&color=red"></a>
 * 9: [BSides Copenhagen 2024](http://www.bsideskbh.dk/) - Copenhagen (Denmark) <a href="https://sessionize.com/bsides-copenhagen-2024"><img alt="CFP BSides Copenhagen 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2016-June-2024&color=red"></a>
 * 9: [DevOpsDays João Pessoa](https://devopsdays.org/events/2024-joao-pessoa/welcome/) - João Pessoa (Brazil)
+* 9-10: [FOSSCOMM 2024](https://2024.fosscomm.gr/) - Thessaloniki (Greece) <a href="https://2024.fosscomm.gr/call-for-papers/"><img alt="CFP FOSSCOMM 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2015-September-2024&color=green"></a>
 * 9-11: [RustLab 2024](https://rustlab.it) - Florence (Italy) <a href="https://sessionize.com/rustlab-2024"><img alt="CFP RustLab 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2001-May-2024&color=red"></a>
 * 11-12: [WasmCon NA](https://events.linuxfoundation.org/wasmcon/program/cfp/) - Salt Lake City (USA) <a href="https://sessionize.com/cncf-hosted-co-located-events-na-2024"><img alt="CFP KubeCon Colocated event NA 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2008-July-2024&color=red"></a>
 * 11-13: [GoLab](https://golab.io) - Florence (Italy) <a href="https://sessionize.com/golab-2024"><img alt="CFP GoLab 2024" src="https://img.shields.io/static/v1?label=CFP&message=until%2012-May-2024&color=red"></a>