add link to comparison

add link to comparison from last version to this version

Author: jlovejoy

RELEASE-NOTES.md

@@ -12,6 +12,6 @@ New licenses/exceptions added: 6
 
 Updated or added license info for source files associated with SPDX License List (.json, scheme, .js files) with CC0-1.0
 
-Various additions to Notes field
+See all PRs for 3.3 here: https://github.com/spdx/license-list-XML/pulls?q=is%3Apr+is%3Aclosed+milestone%3A%223.3+release%22
 
-See all PRs here: https://github.com/spdx/license-list-XML/pulls?q=is%3Apr+is%3Aclosed+milestone%3A%223.3+release%22
+See comparision of changes from 3.2 and 3.3: https://github.com/spdx/license-list-XML/compare/v3.2...v3.3