Update release-notes.txt

Author: KlausBlum

update/release-notes.txt

@@ -4,13 +4,17 @@ https://github.com/openlilylib/LO-ly/wiki/Downloads
 and open it in LibreOffice / OpenOffice.
 
 direct link:
-https://github.com/openlilylib/LO-ly/releases/download/0.5.6/OOoLilyPond-0.5.6.oxt
+https://github.com/openlilylib/LO-ly/releases/download/0.5.7/OOoLilyPond-0.5.7.oxt
 
 
-OOoLilyPond 0.5.6 Release Notes (March 2018)
-================================================
+OOoLilyPond 0.5.7 Release Notes (May 2018)
+==========================================
 
-Hint: If you tried to download the update via the extension manager and got a "403 Forbidden" error message, just try once more.
+* When installing the extension in OpenOffice, the automatic creation of an OLy toolbar failed. This ist fixed now. 
+  Thanks to the anonymous contributor who pointed out this solution in his comment on 
+  https://extensions.openoffice.org/en/project/OOoLilyPond
+
+(Only tested with OpenOffice. Strangely enough, LibreOffice 6.0.2.1 won't let me delete existing toolbars.)
 
 
 Changes to OOoLilyPond 0.5.6 since 0.5.5: