[SPDK] Preparation for SPDK 23.09 release

Hello all,

The merge window for SPDK 23.09 release will close by September 22nd.
Please ensure all patches you believe should be included in the release are=
 merged to 'master' branch by this date.
You can do it by adding a hashtag '23.09' in Gerrit on those patches.

The current set of patches that are tagged and need to be reviewed can be s=
een here:
https://review.spdk.io/gerrit/q/hashtag:%2223.09%22+status:open

On September 22nd new branch 'v23.09.x' will be created, and a patch on it =
will be tagged as release candidate.
Then, by September 29th, a formal release will take place tagging the last =
patch on the branch as SPDK 23.09.

Between release candidate and formal release, only critical fixes shall be =
backported to the 'v23.09.x' branch.
Development can continue without disruptions on 'master' branch.

Thanks,
Tomek