update sorc/jcb hash to remove png files (#1230)

g-w PR [#2782](NOAA-EMC/global-workflow#2782)
and jcb PR [#10](NOAA-EMC/jcb#10) document the
need to remove png files from the `jcb` repository. The files were
removed at
[`8269ce4`](NOAA-EMC/jcb@8269ce4).

This PR updates the `sorc/jcb` hash to
[`8269ce4`](NOAA-EMC/jcb@8269ce4).

Resolves #1229