Does not work for new versioning format

[Azyrod]

Tried to run shulkr --mappings mojang 26.1-snapshot-5 and it failed with RuntimeError: Could not find client mappings for 26.1-snapshot-5

[Azyrod]

Not that as a temporary workaround, we can :

• modify src/minecraft/source.py in _generate_sources_with_mojang add the following arguments to DecompilerMC: "-na", "-dj", "yes", "-dec", "yes", "-dm", "no", "-rmap", "no", "-rjar", "no", "-dd", "no"
• run shulkr once - it will fail after downloading the jar
• run cp DecompilerMC/versions/26.1-snapshot-5/client.jar DecompilerMC/src/26.1-snapshot-5-client-temp.jar
• run shulkr again : it will finish the job.

[lintyourcode]

Mojang released unobfuscated Minecraft JE jars, so DecompilerMC is now archived. We probably don't need it anymore

[Azyrod]

@lintyourcode yes but we still need DecompilerMC for old versions. We don't need it for new unobfuscated versions, but shulkr should still support both