chore(deps): update dependency go to v1.25.4 (#156)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

go.mod

@@ -2,7 +2,7 @@ module github.com/int128/oauth2dev
 
 go 1.24.0
 
-toolchain go1.25.3
+toolchain go1.25.4
 
 require (
 	github.com/google/go-cmp v0.7.0