chore(deps): update module go to 1.20 (#8)

Co-authored-by: Renovate Bot <renovate@whitesourcesoftware.com>

Author: terraform-ibm-modules-ops

tests/go.mod

@@ -1,6 +1,6 @@
 module github.com/terraform-ibm-modules/terraform-ibm-icd-postgresql
 
-go 1.19
+go 1.20
 
 require (
 	github.com/stretchr/testify v1.8.1