Permission denied to mkdir /.docker

[cmoulliard]

Issue

When the step-source-default of a build's pod is executed, then the following error is reported

2021/10/07 12:46:59 warning: unsuccessful cred copy: ".docker" from "/tekton/creds" to "/": 
unable to create destination directory: mkdir /.docker: permission denied

Remark: The builder image used is created using this project: https://github.com/quarkusio/quarkus-buildpacks

Steps to reproduce

• Create a k8s cluster + TLS/Secured container registry using this bash script: https://github.com/snowdrop/k8s-infra/blob/main/kind/kind-tls-secured-reg.sh
• Deploy tekton/shipwright
• Follow steps defined here: https://github.com/halkyonio/r-d/blob/536b94dafa08546672edf8c41e88a5282b739401/buildpack/README.md#3-shipwright-and-buildpack-v3