Added JChateau (#1203)

* Added JChateau

* Update README.md

---------

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

README.md

@@ -340,6 +340,7 @@ All the data (past and coming) are available publicly in JSON:
 * 26-27: [VoxxedDays Bucharest](https://romania.voxxeddays.com/voxxed-days-bucharest-2025/) - Bucharest (Romania) <a href="hhttps://vdbuh2025.cfp.dev/"><img alt="CFP VoxxedDays Bucharest 2025" src="https://img.shields.io/static/v1?label=CFP&message=until%2031-January-2025&color=green"></a>
 * 26-28: [Booster Conference 2025](https://www.boosterconf.no/) - Bergen (Norway) <a href="https://sessionize.com/booster-conference-2025"><img alt="CFP Booster Conference 2025" src="https://img.shields.io/static/v1?label=CFP&message=until%2011-October-2024&color=red"></a>
 * 26-28: [SeleniumConf & AppiumConf Valencia 2025](https://seleniumconf.com/) - Valencia (Spain) <a href="https://sessionize.com/seleniumconf-2025-valencia/"><img alt="CFP SeleniumConf & AppiumConf Valencia 2025" src="https://img.shields.io/static/v1?label=CFP&message=until%2001-December-2024&color=green"></a>
+* 26-29: [JChateau Unconference 2025](https://jchateau.org/) - Cour-Cheverny (France)
 * 27: [Ghana Artificial Intelligence Summit and Awards](https://www.artificialintelligenceghana.com) - Accra (Ghana) <a href="https://www.papercall.io/ghanaaisummit"><img alt="CFP Call for Papers: Ghana's 1st  Artificial Intelligence Summit and Awards" src="https://img.shields.io/static/v1?label=CFP&message=until%2001-November-2024&color=red"></a>
 * 27-28: [Scalar 2025](https://scalar-conf.com) - Warsaw (Poland) <a href="https://sessionize.com/scalar-2025"><img alt="CFP Scalar 2025" src="https://img.shields.io/static/v1?label=CFP&message=until%2013-October-2024&color=red"></a>
 * 27-28: [ScanAgile25](https://scan-agile.org/) - Helsinki (Finland) <a href="https://sessionize.com/scanagile25/"><img alt="CFP ScanAgile25" src="https://img.shields.io/static/v1?label=CFP&message=until%2029-September-2024&color=red"></a>