Update Go version to 1.25.4

See the release history: https://go.dev/doc/devel/release#go1.25.4.

Author: arnested

go.mod

@@ -1,6 +1,6 @@
 module github.com/arnested/sshfpgo
 
-go 1.25.3
+go 1.25.4
 
 require (
 	github.com/Showmax/go-fqdn v1.0.0