Permission errors when using Kube attach and non-root user
## Summary
I am using the gitlab-runner Helm chart to deploy a runner to K8s. The executor is configured to run as a non-root user, and `FF_USE_LEGACY_KUBERNETES_EXECUTION_STRATEGY` is set to false (use attach instead of exec).
I am using the 13.4.0 runner.
Relevant sections in my values.yaml are:
```
pod_security_context:
run_as_non_root: true
run_as_user: 65000
run_as_group: 65000
fs_group: 65000
supplemental_groups: [412]
serviceAccountName: gitlab-executor
env:
FF_USE_LEGACY_KUBERNETES_EXECUTION_STRATEGY: false
```
Under this configuration, I encounter multiple permission errors:
1. Permission denied when running `chmod -R 777 s.logsDir()` in the `change-logs-permissions` init container
2. Permission denied when trying to create `s.Build.FullProjectDir()`
3. Permission denied when trying to create `CI_SERVER_TLS_CA_FILE` in the temporary directory (s.Build.TmpProjectDir())
## Steps to reproduce
Create a Kubernetes gitlab-runner via Helm with the values.yaml configuration listed above. Replace the `65000` ID values with the user and group ID of a non-root user.
## Actual behavior
Encounter permission denied errors (see above).
## Expected behavior
No permission errors.
## Relevant logs and/or screenshots
See above.
## Environment description
See above.
### Used GitLab Runner version
13.4.0
## Possible fixes
I will be creating a MR with a proposed fix.
Related MR: https://gitlab.com/gitlab-org/gitlab-runner/-/merge_requests/2236
@ggeorgiev\_
issue