WoT: Update 1.21.0 Release Dates

Patch 1.21.0 is going to be released since May, 30

Release dates:

• ASIA: May, 30
• NA: May, 30
• EU: May, 31

The mods folders will be renamed to: ./mods/1.21.0.0/ and ./res_mods/1.21.0.0/