Updated release notes for release v3.1-5 and fixed date format in spec file

ReleaseNotes.md

-# Next release
+# v3.1-5
 
 ## Summary
 
+This release is a bug fix release.
 
 ### Features
 
@@ -18,6 +19,7 @@
 - Reinstates "cta-admin failedrequest --summary" option
 - cta/CTA#865 Empty the RetrieveQueue in the case of cancellation of a retrieve request when the drive is down
 
+
 # v3.1-4
 
 ## Summary
@@ -35,6 +37,7 @@ command-line tool based on operator requests and removes the deprecated
 - cta/CTA#846 cta-admin tapefile ls: list by fileid
 - cta/CTA#840 Remove cta-objectstore-unfollow-agent from cta-objectstore-tools
 
+
 # v3.1-3
 
 ## Summary

cta.spec.in

@@ -474,7 +474,7 @@ Currently contains a helper for the client-ar script, which should be installed
 %attr(0755,root,root) /usr/bin/cta-client-ar-abortPrepare
 
 %changelog
-* Thu 20 Aug 2020 julien.leduc (at) cern.ch - 3.1-5
+* Thu Aug 20 2020 julien.leduc (at) cern.ch - 3.1-5
 - cta/CTA#863 Prevent SQLite database files from being used as the CTA catalogue database backend
 - cta/CTA#861 cta-admin comment column is flush left
 - cta/CTA#862 Unable to delete tabtest tape pool because it is in an archive route