Unable to load in-cluster configuration

I wrote a go app which will list all the constraint violation in the cluster.When tried to build it as docker image and run it in my pod and getting this error.

pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: opa
  labels:

    name: opa
spec:
  containers:
  - name: opa
    image: sathya0803/opa-task:latest
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
    ports:
      - containerPort: 8000

ERROR:

revaa@revaa-Lenovo-E41-25:~/opa$ kubectl logs opa
2021/07/30 05:50:12 Using incluster K8S client
2021/07/30 05:50:12 Using incluster K8S client
2021/07/30 05:50:12 err:k8srequiredlabels.constraints.gatekeeper.sh is forbidden: User"system:serviceaccount:default:opa" cannot list resource "k8srequiredlabels" in API group "constraints.gatekeeper.sh" at 
 the cluster scope
 2021/07/30 05:50:12 listing constraints violations...
 2021/07/30 05:50:12 data: null

As mentioned by @Ferdy Pruis the service account you are using does not have the necessary privileges to perform the task using the kubernetes API. Check the below RBAC to provision your own service account with the appropriate permissions.

This will grant the default service account view permissions. A more secure approach would probably be to create a new service account, grant it the view permissions, and then assign that service account to deployment configuration.

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: default-view
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: view
subjects:
  - kind: ServiceAccount
    name: default
    namespace: default

Refer these links for creating and managing SA and IAM.