Update operational GFS version to v16.3.24 in index.rst (NOAA-EMC#3650)

Update the operational GFS version noted within the
Read-The-Docs front page. The version is now v16.3.24.

Refs NOAA-EMC#3590

Author: KateFriedman-NOAA

docs/source/index.rst

@@ -10,7 +10,7 @@ Status
 ======
 
 * State of develop (HEAD) branch: GFSv17+ development
-* State of operations (dev/gfs.v16 branch): GFS v16.3.13 `tag: [gfs.v16.3.13] <https://github.com/NOAA-EMC/global-workflow/releases/tag/gfs.v16.3.13>`_
+* State of operations (dev/gfs.v16 branch): GFS v16.3.24 `tag: [gfs.v16.3.24] <https://github.com/NOAA-EMC/global-workflow/releases/tag/gfs.v16.3.24>`_
 
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