Comment out runAsUser and runAsGroup in values.yaml (#618)

Since [PR 2456](sourcegraph/sourcegraph#2456) in
the Sourcegraph repo, support for the default value of -1 for the
`KUBERNETES_RUN_AS_USER` and `KUBERNETES_RUN_AS_GROUP` Executor
environment variables has been removed - those environment variables now
require either blank values or non-negative integers in the range [0,
2147483647], to match the range for Unix UIDs and GIDs.

This PR updates `charts/sourcegraph-executor/k8s/values.yaml` so that
`runAsUser` and `runAsGroup` are commented out, with comments to explain
that the user can uncomment them to use them. Having those settings
commented out causes `KUBERNETES_RUN_AS_USER` and
`KUBERNETES_RUN_AS_GROUP` in
`charts/sourcegraph-executor/k8s/templates/executor.ConfigMap.yaml` to
be blank, which is the new default value.

### Checklist

- [ ] Follow the [manual testing
process](https://github.com/sourcegraph/deploy-sourcegraph-helm/blob/main/TEST.md)
- [ ] Update
[changelog](https://github.com/sourcegraph/deploy-sourcegraph-helm/blob/main/charts/sourcegraph/CHANGELOG.md)
- [ ] Update [Kubernetes update
doc](https://docs.sourcegraph.com/admin/updates/kubernetes)

### Test plan

A Helm deployment is successful and does not fail with errors like
`KUBERNETES_RUN_AS_USER must be a UID in the range 0 to 2,147,483,647,
but got "-1".`

Author: peterguy

charts/sourcegraph-executor/k8s/README.md

@@ -77,8 +77,8 @@ In addition to the documented values, the `executor` and `private-docker-registr
 | executor.kubernetesJob.resources.limits.memory | string | `"12Gi"` | The maximum memory for a job. |
 | executor.kubernetesJob.resources.requests.cpu | string | `""` | The requested CPU for a job. |
 | executor.kubernetesJob.resources.requests.memory | string | `"1Gi"` | The requested memory for a job. |
-| executor.kubernetesJob.runAsGroup | int | `-1` | The group ID to run Kubernetes jobs as. |
-| executor.kubernetesJob.runAsUser | int | `-1` | The user ID to run Kubernetes jobs as. |
+| executor.kubernetesJob.runAsGroup | int | `nil`; accepts [0, 2147483647] | The group ID to run Kubernetes jobs as. |
+| executor.kubernetesJob.runAsUser | int | `nil`; accepts [0, 2147483647] | The user ID to run Kubernetes jobs as. |
 | executor.log.format | string | `"condensed"` |  |
 | executor.log.level | string | `"warn"` | Possible values are `dbug`, `info`, `warn`, `eror`, `crit`. |
 | executor.log.trace | string | `"false"` |  |

charts/sourcegraph-executor/k8s/values.yaml

@@ -94,10 +94,12 @@ executor:
   kubernetesJob:
     # -- The number of seconds after which a Kubernetes job will be terminated.
     deadline: "1200"
-    # -- The user ID to run Kubernetes jobs as.
-    runAsUser: -1
-    # -- The group ID to run Kubernetes jobs as.
-    runAsGroup: -1
+    # -- (int) The user ID to run Kubernetes jobs as.
+    # @default -- `nil`; accepts [0, 2147483647]
+    runAsUser: 
+    # -- (int) The group ID to run Kubernetes jobs as.
+    # @default -- `nil`; accepts [0, 2147483647]
+    runAsGroup: 
     # -- The group ID which is set on the job PVC file system. 
     fsGroup: "1000"
     resources: