argocd app create sealed-secrets --repo https://kubernetes-charts.storage.googleapis.com --helm-chart sealed-secrets --revision '1.5.0' --dest-server https://kubernetes.default.svc --dest-namespace kube-system 
argocd app sync sealed-secrets

brew install kubeseal

export username=... ;# your Github username 
echo -n bar | kubectl create secret generic ${username}-mysecret --dry-run --from-file=foo=/dev/stdin -o json > mysecret.json

kubeseal --cert https://argo-cd-kubecon.apps.argoproj.io/secret/cert.pem < mysecret.json > mysealedsecret.json

rm mysecret.json

git add mysealedsecret.json
git commit -am 'Add secret'
git push

argocd app create ${username}-secrets --repo https://github.com/${username}/secrets.git --path . --revision HEAD --dest-server https://kubernetes.default.svc --dest-namespace default
argocd app sync ${username}-secrets

kubectl -n default get secrets -o yaml

argocd app delete ${username}-secrets
argocd app delete sealed-secrets