JCR-4420: Release Notes: term "SHA1" no longer allowed (ported to 2.12)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/branches/2.12@1856859 13f79535-47bb-0310-9956-ffa450edef68

RELEASE-NOTES.txt

@@ -68,7 +68,7 @@ This release consists of a single source archive packaged as a zip file.
 The archive can be unpacked with the jar tool from your JDK installation.
 See the README.txt file for instructions on how to build this release.
 
-The source archive is accompanied by SHA1 and SHA512 checksums and a
+The source archive is accompanied by an SHA512 checksum and a
 PGP signature that you can use to verify the authenticity of your
 download. The public key used for the PGP signature can be found at
 https://www.apache.org/dist/jackrabbit/KEYS.