Issue Description: Web files are not matched with plugin version: All files need to be same version (undefined) - try refreshing browser cache (shift-reload)

• Dynmap Version: Dynmap-3.1-beta5-spigot.jar
• Server Version: Paper 1.16.4
• Pastebin of Configuration.txt: https://pastebin.com/94hEd9pm
• Server Host (if applicable): My own dedicated
• Steps to Replicate: I have dynmap installed with Nginx server, i use a symbolic link from the plugin folder to /var/www/eterniaserver.com.br/dynmap (the dynmap url of my site are eterniaserver.com.br/dynmap)

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

This usually happens when the plugin is updated and goes away with time. I'm going to close this due to age but please reply if you still need help