all: upgrade go directive to at least 1.25.0 [generated]

By now Go 1.26.0 has been released, and Go 1.24 is no longer supported
per the Go Release Policy (see https://go.dev/doc/devel/release#policy).

See go.dev/doc/godebug#go-125 for GODEBUG changes relevant to Go 1.25.

For golang/go#69095.

[git-generate]
(cd . && go get go@1.25.0 && go mod tidy)

Change-Id: Ifd87f1cd8d96659db781537c2e424568a8384410
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/744560
Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>

Author: gopherbot

go.mod

@@ -1,5 +1,5 @@
 module golang.org/x/oauth2
 
-go 1.24.0
+go 1.25.0
 
 require cloud.google.com/go/compute/metadata v0.3.0