www/tgpt: Update Go version to 1.22 and used go modules
In recent update to the port, I forgot to update the used go modules.
Now, I am updating them.
PR: 280555 279620
Fixes: fce4a9245139 (Update to 2.8.0)
MFH: 2024Q3
(cherry picked from commit 39a5c2d0b3e67acc54ee0189dbc3a4205b1abc97)