fix(relay): Fix Relay docker commands, registry, nonroot (#14955)

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## DESCRIBE YOUR PR

- The permission change no longer works, due to Relay having a different
base docker container. I opted to use busybox to make the permission
change (with the new user/group id) to make it fully copy pastable, the
alternative would be a `sudo chown` from the host.
- Fixed the `$(pwd)` quoting, this would fail on paths with spaces.
- Switched the registry to ghcr.io as the dockerhub image is seemingly
deprecated
<img width="1165" height="131" alt="image"
src="https://github.com/user-attachments/assets/0e1ff9bc-0d71-4a42-946b-b45e13b44769"
/>

Fixes: INGEST-579

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [x] Checked Vercel preview for correctness, including links
- [x] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

Author: Dav1dde

docs/product/relay/getting-started.mdx

@@ -9,7 +9,7 @@ Getting started with [Relay](/product/relay/) is as simple as using the default
 <Alert>
 
 The Relay server is called `relay`. Download binaries from [GitHub
-Releases](https://github.com/getsentry/relay/releases). A Docker image is provided on [DockerHub](https://hub.docker.com/r/getsentry/relay/).
+Releases](https://github.com/getsentry/relay/releases). A Docker image is provided on the [Github Container Registry](https://github.com/getsentry/relay/pkgs/container/relay).
 
 </Alert>
 
@@ -30,18 +30,14 @@ container and copying in the files.
 
 ```shell {tabTitle:Run in Docker}
 # Adjust permissions for the configuration directory
-# The :z option is only necessary on selinux.
-# See https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label.
-docker run --rm -it                  \
-  -v $(pwd)/config/:/work/.relay/:z  \
-  --entrypoint bash                  \
-  getsentry/relay                    \
-  -c 'chown -R relay:relay /work/.relay'
+chown -R 65532:65532 ./config
 
 # Generate the configuration
-docker run --rm -it                  \
-  -v $(pwd)/config/:/work/.relay/:z  \
-  getsentry/relay                    \
+# The :z option is only necessary on selinux.
+# See https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label.
+docker run --rm -it                   \
+  -v "$(pwd)"/config/:/work/.relay/:z \
+  ghcr.io/getsentry/relay             \
   config init
 ```
 
@@ -128,9 +124,9 @@ To register Relay with Sentry:
 1. Copy the contents of the public key, either by inspecting the `credentials.json` file or by running:
 
    ```shell {tabTitle:Run in Docker}
-   docker run --rm -it                \
-     -v $(pwd)/config/:/work/.relay/  \
-     getsentry/relay                  \
+   docker run --rm -it                 \
+     -v "$(pwd)"/config/:/work/.relay/ \
+     ghcr.io/getsentry/relay           \
      credentials show
    ```
 
@@ -154,10 +150,10 @@ This process registers Relay with Sentry so it is ready to send messages. See
 After registering Relay with Sentry, it is ready to run:
 
 ```shell {tabTitle:Run in Docker}
-docker run --rm -it                \
-  -v $(pwd)/config/:/work/.relay/  \
-  -p 3000:3000                     \
-  getsentry/relay                  \
+docker run --rm -it                 \
+  -v "$(pwd)"/config/:/work/.relay/ \
+  -p 3000:3000                      \
+  ghcr.io/getsentry/relay           \
   run
 ```
 
@@ -181,10 +177,10 @@ Refer to the [Logging](../monitoring/#logging) page for more information on how
 If you moved your config folder (for example, for security reasons), use the `--config` option to specify the location:
 
 ```shell {tabTitle:Run in Docker}
-docker run --rm -it                \
-  -v $(pwd)/config/:/etc/relay/    \
-  -p 3000:3000                     \
-  getsentry/relay                  \
+docker run --rm -it               \
+  -v "$(pwd)"/config/:/etc/relay/ \
+  -p 3000:3000                    \
+  ghcr.io/getsentry/relay         \
   run --config /etc/relay/
 ```