all: upgrade go directive to at least 1.26.0 [generated]

By now Go 1.27.0 has been released, and Go 1.25 is no longer supported
per the Go Release Policy (see https://go.dev/doc/devel/release#policy).

See https://go.dev/doc/godebug#go-126 for GODEBUG setting changes
relevant to Go 1.26.

For golang/go#69095.

[git-generate]
(cd . && go get go@1.26.0 && go mod tidy)
(cd x509roots/fallback && go get go@1.26.0 && go mod tidy)

Change-Id: I54826e019edd4e12ad821915b1d102de719bfb31
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/817981
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Gopher Robot <gobot@golang.org>

Author: gopherbot

go.mod

@@ -1,6 +1,6 @@
 module golang.org/x/crypto
 
-go 1.25.0
+go 1.26.0
 
 require (
 	golang.org/x/net v0.57.0 // tagx:ignore

x509roots/fallback/go.mod

@@ -1,3 +1,3 @@
 module golang.org/x/crypto/x509roots/fallback
 
-go 1.25.0
+go 1.26.0