feat(externaldns): upgrade to 1.21.1, fix sources for installed CRDs

- Bump chart from 1.19.0 to 1.21.1 (app v0.19.0 -> v0.21.0)
- Remove gateway-tcproute source (TCPRoute CRD not installed)
- Add gateway-tlsroute source (TLSRoute CRD is installed)

apps/overlays/au-syd1/externaldns/kustomization.yaml

@@ -8,7 +8,7 @@ resources:
 helmCharts:
   - name: external-dns
     repo: https://artifactapi.k8s.syd1.au.unkin.net/api/v1/virtual/helm
-    version: "1.19.0"
+    version: "1.21.1"
     releaseName: externaldns
     namespace: externaldns
     valuesFile: values.yaml