internal/goversion: update Version to 1.25

Go 1.25 is in the process of being opened for development (to be
eventually released). This change marks the very beginning of its
development cycle, updating the Version value accordingly.

For #40705.
For #70525.

Change-Id: If673d4aeddc376fefe6bddc3ec2704ca91245777
Reviewed-on: https://go-review.googlesource.com/c/go/+/646155
Reviewed-by: Carlos Amedee <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: cherrymui

src/internal/goversion/goversion.go

@@ -9,4 +9,4 @@ package goversion
 //
 // It should be updated at the start of each development cycle to be
 // the version of the next Go 1.x release. See go.dev/issue/40705.
-const Version = 24
+const Version = 25