Add 'include: dns_records' to TLS configuration by ID lookup in data …

…source (#392)

It was missing and dns_records weren't populated when using

data "fastly_tls_configuration" "configuration_by_id" {
  id = data.fastly_tls_configuration.default_configuration.id
}

but they were populated when using any other search filter. This was
because the lookup by ID used the GetCustomTLSConfiguration call in
go-fastly whereas the others used ListCustomTLSConfigurations and
filtered them locally. Therefore the former call was missing the
required flag.

fastly/data_source_fastly_tls_configuration.go

@@ -111,7 +111,8 @@ func dataSourceFastlyTLSConfigurationRead(_ context.Context, d *schema.ResourceD
 
 	if v, ok := d.GetOk("id"); ok {
 		config, err := conn.GetCustomTLSConfiguration(&fastly.GetCustomTLSConfigurationInput{
-			ID: v.(string),
+			ID:      v.(string),
+			Include: "dns_records",
 		})
 		if err != nil {
 			return diag.FromErr(err)