Check the presence of the images after releasing

**Unrelated:** I think we should also check the presence of the images after releasing. Just to double check. Do you think this check should be part as the release process @wallrj?

---

To check that the automation went through, check that the 3 public images are available:

```bash
docker run -it quay.io/jetstack/preflight:v0.1.49 version
docker run -it quay.io/jetstack/venafi-agent:v0.1.49 version
docker run -it registry.venafi.cloud/venafi-agent/venafi-agent:v0.1.49 version
```

Then, you will need to use venctl to check the two private registries:

1. ```
curl -sSfL https://dl.venafi.cloud/venctl/latest/installer.sh | bash
```
2. Go to https://ven-tlspk.venafi.cloud/platform-settings/user-preferences?key=api-keys. Log in using the username `admin0@tlspk.qa.venafi.io` and the [password here](https://venafi.atlassian.net/wiki/spaces/CT/pages/2115404149/Production+Accounts#Users)). Copy the API key for the next step (click "Generate" if the API key doesn't already exist).
3. Set the APIKEY env variable:
```
APIKEY=...
```
4. Docker login to private-registry.venafi.cloud:
```bash
venctl iam service-account registry create --name "$USER Temp" \
--vcp-region US \
--output dockerconfig \
--output-file dockerconfig \
--api-key $APIKEY
docker login private-registry.venafi.cloud \
| --username $(cat dockerconfig | jq '.. | select(.username?).username' -r) \
| --password $(cat dockerconfig | jq '.. | select(.username?).auth | @base64d' -r | cut -d: -f2) |
```
5. Go to https://ven-tlspk-eu.venafi.cloud/platform-settings/user-preferences?key=api-keys. Log in using the username `admin0@tlspk.qa.venafi.io` and the [password here](https://venafi.atlassian.net/wiki/spaces/CT/pages/2115404149/Production+Accounts#Users)). Click "Generate" and copy the API key for the next step.
6. Set the APIKEY env variable:
```
APIKEY=...
```
8. Docker login to private-registry.venafi.eu:

```bash
venctl iam service-account registry create --name "$USER Temp" \
--vcp-region EU \
--output dockerconfig \
--output-file dockerconfig \
--api-key $APIKEY
docker login private-registry.venafi.eu \
| --username $(cat dockerconfig | jq '.. | select(.username?).username' -r) \
| --password $(cat dockerconfig | jq '.. | select(.username?).auth | @base64d' -r | cut -d: -f2) |
```

And now:

```bash
docker run -it private-registry.venafi.cloud/venafi-agent/venafi-agent:v0.1.49 version
docker run -it private-registry.venafi.eu/venafi-agent/venafi-agent:v0.1.49 version
```

_Originally posted by @maelvls in https://github.com/jetstack/jetstack-secure/issues/548#issuecomment-2222998317_