rpm: fix bogus date in changelog

fixes: warning: bogus date in %changelog: Fri Oct 22 2020 julien.leduc (at) cern.ch - 3.1-8
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>

cta.spec.in

@@ -598,7 +598,7 @@ This package contains .repo files, gpg keys and yum-versionlock configuration fo
 - cta/CTA#907 For backpressure, the EOS free space can be fetched by calling an external script
 - cta/CTA#917 Corrected the bug in the cta-admin showqueues command in the case ArchiveForUser and ArchiveForRepack exist for the same tapepool
 - cta/CTA#919 Archive queue oldestjobcreationtime is now updated at each pop from the ArchiveQueue
-* Fri Oct 22 2020 julien.leduc (at) cern.ch - 3.1-8
+* Thu Oct 22 2020 julien.leduc (at) cern.ch - 3.1-8
 - CTA software Recommended Access Order (RAO) implemented for LTO drives
 - cta-admin repack ls tabular output improvements
 - Upstream EOS 4.8.24-1