Try remove https from docker registry

tekton-pipeline/resources/secrets.yaml

@@ -15,7 +15,7 @@ metadata:
   name: basic-docker-user-pass
   annotations:
     # Replace <docker_registry_url> with your docker registry URL (e.g. https://my-acr.azurecr.io)
-    tekton.dev/docker-0: https://registry.hub.docker.com
+    tekton.dev/docker-0: registry.hub.docker.com
 type: kubernetes.io/basic-auth
 
 ---

tekton-pipeline/triggers/trigger-template.yaml

@@ -37,7 +37,7 @@ spec:
       params:
       - name: url
         # Replace <docker_registry_name> with your docker registry name (e.g. my-acr.azurecr.io)
-        value: https://registry.hub.docker.com
+        value: registry.hub.docker.com
       type: image
   - apiVersion: tekton.dev/v1alpha1
     kind: PipelineRun