Re-vendor queue-worker publisher for reconnect

- re-vendor queue-worker for publisher via 0.6.0
- bump queue-worker version to 0.6.0 in docker-compose.yml for
AMD64
- use new naming for NATS of nats -> NATS in variables where
required
- add default reconnect of 60 times, 2 seconds apart.

Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>

gateway/vendor/github.com/openfaas/nats-queue-worker/nats/client.go

@@ -0,0 +1,8 @@
+package nats
+
+import "regexp"
+
+var supportedCharacters = regexp.MustCompile("[^a-zA-Z0-9-_]+")
+func GetClientID(value string) string {
+	return supportedCharacters.ReplaceAllString(value, "_")
+}

gateway/vendor/github.com/openfaas/nats-queue-worker/nats/client_test.go

@@ -0,0 +1,23 @@
+package nats
+
+import (
+	"testing"
+)
+
+func TestGetClientID(t *testing.T) {
+	clientID := GetClientID("computer-a")
+	want := "computer-a"
+	if clientID != want {
+		t.Logf("Want clientID: `%s`, but got: `%s`\n", want, clientID)
+		t.Fail()
+	}
+}
+
+func TestGetClientIDWhenHostHasUnsupportedCharacters(t *testing.T) {
+	clientID := GetClientID("computer-a.acme.com")
+	want := "computer-a_acme_com"
+	if clientID != want {
+		t.Logf("Want clientID: `%s`, but got: `%s`\n", want, clientID)
+		t.Fail()
+	}
+}