Update module go to 1.19 (#27)

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

Author: renovate[bot]

go.mod

@@ -1,6 +1,6 @@
 module github.com/k0swe/wsjtx-go/v4
 
-go 1.18
+go 1.19
 
 require (
 	github.com/leemcloughlin/jdn v0.0.0-20201102080031-6f88db6a6bf2