Update watch file

debian/watch

@@ -1,4 +1,5 @@
 
 version=4
-https://github.com/latchset/@PACKAGE@/releases \
+opts="searchmode=plain,filenamemangle=s/$/.tar.gz/" \
+https://api.github.com/repos/latchset/@PACKAGE@/releases \
     /latchset/@PACKAGE@/releases/download/[^/]+/@PACKAGE@-([0-9][.0-9]*)@ARCHIVE_EXT@