Updated ReleaseNotes.md and cta.spec.in for v3.1-8 version

ReleaseNotes.md

+# v3.1-8
+
+## Summary
+
+This release contains the CTA software Recommended Access Order (RAO) implemented for LTO drives to improve retrieve performances
+
+### Features
+
+- CTA software Recommended Access Order (RAO) implemented for LTO drives
+
 # v3.1-7
 
 ## Summary

cta.spec.in

@@ -490,6 +490,8 @@ Currently contains a helper for the client-ar script, which should be installed
 %attr(0755,root,root) /usr/bin/cta-client-ar-abortPrepare
 
 %changelog
+* Fri Sep 25 2020 julien.leduc (at) cern.ch - 3.1-8
+- CTA software Recommended Access Order (RAO) implemented for LTO drives
 * Wed Sep 23 2020 julien.leduc (at) cern.ch - 3.1-7
 - cta/CTA#893 Corrected slowliness of RdbmsCatalogue::getArchiveFileToRetrieveByArchiveFileId()
 * Mon Sep 21 2020 julien.leduc (at) cern.ch - 3.1-6