feat(externaldns): upgrade to 1.21.1, fix sources for installed CRDs (#143)

## Changes

- Upgrade external-dns chart from 1.19.0 → 1.21.1 (app v0.19.0 → v0.21.0)
- Remove `gateway-tcproute` source — `TCPRoute` CRD is not installed, causing crash-loop
- Add `gateway-tlsroute` source — `TLSRoute` CRD is installed (Gateway API 1.5.1)

## Why

The pod was crash-looping every minute with `failed to list *v1alpha2.TCPRoute: the server could not find the requested resource` because the TCPRoute CRD doesn't exist in this cluster. TLSRoute was previously removed but its CRD does exist.

Reviewed-on: #143

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

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

@@ -26,7 +26,6 @@ sources:
   - ingress
   - gateway-httproute
   - gateway-grpcroute
-  - gateway-tcproute
 
 # Environment variables for TSIG secret and algorithm from Vault
 env: