Upgrade XRootD version once next XRootD vanilla release is made available

Issue https://gitlab.cern.ch/cta/operations/-/issues/1696 describes a problem on the FST garbage collector caused by a bug in XRootD that affects EOS.

A fix has already been added to the XRootD project, and included in EOS through the custom RPM eos-xrootd-5.8.2-1.

However, in the case of CTA we still need to wait for the next vanilla XRootD version to be released (5.8.3)...

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The purpose of this ticket is to keep track of this requirement until the next version of XRootD is made available.