d/watch: Adapt to Github website changes

debian/watch

@@ -1,2 +1,9 @@
 version=4
-https://github.com/ostreedev/ostree/releases .*/libostree-(\d\S*)\.tar\.xz
+# Upstream releases official Autotools 'make dist' tarballs, so we use
+# those in preference to git tags
+opts="\
+    compression=xz, \
+    dversionmangle=s/\+(?:git)?[0-9]*(?:\+g[0-9a-f]*)//, \
+    downloadurlmangle=s#/tag/#/download/#;s#(v?@ANY_VERSION@)$#$1/libostree-$2.tar.xz#, \
+    filenamemangle=s#v?@ANY_VERSION@#@PACKAGE@-$1.tar.xz#" \
+https://github.com/ostreedev/@PACKAGE@/tags .*/releases/tag/v?@ANY_VERSION@