configure.ac: Add more details on how to do a release

Closes: ostreedev#1928
Approved by: cgwalters

configure.ac

@@ -1,8 +1,11 @@
 AC_PREREQ([2.63])
-dnl If doing a final release, remember to follow the instructions to
-dnl update libostree-released.sym from libostree-devel.sym, and update the checksum
-dnl in test-symbols.sh, and also set is_release_build=yes below.  Then make
-dnl another post-release commit to bump the version, and set is_release_build=no.
+dnl To do a release: follow the instructions to update libostree-released.sym from
+dnl libostree-devel.sym, update the checksum in test-symbols.sh, set is_release_build=yes
+dnl below. Then make another post-release commit to bump the version and set
+dnl is_release_build=no.
+dnl Seed the release notes with `git-shortlog-with-prs <previous-release>..`. Then use
+dnl `git-evtag` to create the tag and push it. Finally, create a GitHub release and attach
+dnl the tarball from `make dist`.
 m4_define([year_version], [2019])
 m4_define([release_version], [5])
 m4_define([package_version], [year_version.release_version])