Doc: Fix a broken link in an ssh-related warning message (#17294)
Doc: Fix a broken link in an ssh-related warning message (#17294)

Warning Message:
```
    #####################################################
    #  WARNING: You should set dags.gitSync.knownHosts  #
    #####################################################

    You are using ssh authentication for your gitsync repo, however you currently have SSH known_hosts verification disabled,
    making you susceptible to man-in-the-middle attacks!

    Information on how to set knownHosts can be found here:
    https://airflow.apache.org/docs/helm-chart/latest/production-guide.html#knownhosts
```
broken: https://airflow.apache.org/docs/helm-chart/latest/production-guide.html#knownhosts
fixed: https://airflow.apache.org/docs/helm-chart/stable/production-guide.html#knownhosts

Co-authored-by: Matt Rixman <27f40c4d2b9178525319dcf3512fafbf93f29822@users.noreply.github.com>
dhuang/incubator-airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,bolkedebruin/airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,mistercrunch/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,dhuang/incubator-airflow,mistercrunch/airflow,apache/incubator-airflow,mistercrunch/airflow,nathanielvarona/airflow,bolkedebruin/airflow,Acehaidrey/incubator-airflow,apache/airflow,cfei18/incubator-airflow,lyft/incubator-airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,apache/airflow,apache/airflow,lyft/incubator-airflow,dhuang/incubator-airflow,mistercrunch/airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,nathanielvarona/airflow,apache/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,nathanielvarona/airflow,apache/incubator-airflow,cfei18/incubator-airflow,bolkedebruin/airflow,apache/airflow,bolkedebruin/airflow