Not working on 1.21.10

[eirikh1996]

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Issue Description: When loading and enabling Dynmap on 1.21.10, the plugin fails to load and enable

• Dynmap Version: v3.7-SNAPSHOT-968
• Server Version: Paper version 1.21.10
• Pastebin of Configuration.txt: Not available since it fails to load
• Server Host (if applicable): selfhosted
• Pastebin of crashlogs or other relevant logs: https://pastebin.com/NmEW4Pjz
• Other Relevant Data/Screenshots: I'm using this texture pack and these plugins and my map is from alpha .8
• Steps to Replicate: 1. Install dynmap on a 1.21.10 server, 2. Run server, 3. See error in server log

[ ] I have looked at all other issues and this is not a duplicate
[ ] I have been able to replicate this

[reusteur73]

Versions 1.21.9 and 1.21.10 are not officially supported yet. Please see #4239 and #4240.