Update github ssh rsa hostkey for uploads

[Scott Little]

Brief Description
-----------------
Guthub's hostkey was compromised. They have issued a new one.
Now our Zuul jobs to mirror StarlingX updates to GitHub are
failing until the host hey is updated.

Github's announcement...
https://github.blog/2023-03-23-we-updated-our-rsa-ssh-host-key/

Refer to this update for an example of what needs to be done...
https://review.opendev.org/c/openstack/project-config/+/878616

Severity
--------
Major

Steps to Reproduce
------------------
Merge update to StarlingX at OpenDev.
Note that starlingX at Github does not get the same update.

Expected Behavior
------------------
Github mirrors Opendev for StarlingX updates.

Actual Behavior
----------------
Github hasn't seen updates for over a week

Reproducibility
---------------
100% reproducible

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
April 1, 2023

Last Pass
---------
March 23, 2023

Timestamp/Logs
--------------
https://zuul.opendev.org/t/openstack/build/b5ed0f63a82845d7873c84a7db9f278f

Test Activity
-------------
N/A

Workaround
----------
N/A

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/integ/+/879507

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Scott Little <email address hidden>" on branch: master
Review: https://review.opendev.org/c/starlingx/integ/+/879507