Issue Description: world created in 1.16.5, updated server to 1.18.2, ran --forceUpgrade on the first boot of the new server, after succesfull start I get the message: [09:42:37 WARN]: [dynmap] Unknown chunk dataVersion: 2975
the map renders fine, just a warning

• Dynmap Version: 3.4-beta-3-777
• Server Version: paper 1.18.2 - 274
• Pastebin of Configuration.txt: https://pastebin.com/SKzpG2Wh
• Server Host (if applicable): Selfhosted
• Pastebin of crashlogs or other relevant logs: https://pastebin.com/HghNUep1
• Other Relevant Data/Screenshots: none

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

discord user "TAS 2012" found this bug, writing this report to keep track of the issue.

Added versions for 1.18.2, 1.19 and (likely) 1.19.1 GA