Update module lib/pq to v1.7.0 (#581)

Update module lib/pq to v1.7.0

Reviewed-on: https://kolaente.dev/vikunja/api/pulls/581

vendor/github.com/lib/pq/doc.go

@@ -243,5 +243,21 @@ bytes by the PostgreSQL server.
 You can find a complete, working example of Listener usage at
 https://godoc.org/github.com/lib/pq/example/listen.
 
+
+Kerberos Support
+
+
+If you need support for Kerberos authentication, add the following to your main
+package:
+
+	import "github.com/lib/pq/auth/kerberos"
+
+	func init() {
+		pq.RegisterGSSProvider(func() (pq.Gss, error) { return kerberos.NewGSS() })
+	}
+
+This package is in a separate module so that users who don't need Kerberos
+don't have to download unnecessary dependencies.
+
 */
 package pq