HPCC-11318 Added missing </center> tag

Fixes HPCC-11318

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #5780 from GordonSmith/HPCC-11318

HPCC-11318 Added missing </center> tag

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>