Fix typo in juliahep.md

A workshop in 2204 looks a bit too far...  :D 
```
2204 -> 2024
```

_activities/juliahep.md

@@ -30,5 +30,5 @@ The JuliaHEP organisation website is <http://www.juliahep.org/>.
 
 We plan for a series of **JuliaHEP workshops** with the aim to provide an environment to discuss and promote the usage of Julia in the HEP community at large.
 
-- The second [workshop](https://indico.cern.ch/e/juliahep2024) will be held from 30 September - 4 October 2204 at CERN.
+- The second [workshop](https://indico.cern.ch/e/juliahep2024) will be held from 30 September - 4 October 2024 at CERN.
 - The first [workshop](https://indico.cern.ch/event/1292759/) was held from 6-9 November 2023 at ECAP (Erlangen Centre for Astroparticle Physics). The notes of the concluding discussion session can be found [here](https://notes.desy.de/s/EE_fpNX-T).