chore(deps): update go toolchain directive to v1.26.3 (#634)

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

Author: renovate[bot]

go.mod

@@ -2,7 +2,7 @@ module github.com/fclairamb/ftpserverlib
 
 go 1.24.0
 
-toolchain go1.26.2
+toolchain go1.26.3
 
 require (
 	github.com/secsy/goftp v0.0.0-20200609142545-aa2de14babf4