Reminder: keep jhbuild dependencies updated

[Michael Catanzaro <mcatanzaro gnome org>]

Hi all,

A reminder to all maintainers: when bumping required versions of any of
your dependencies, please be sure to check jhbuild to make sure it has
the appropriate required versions, and update the modulesets if not. We
had multiple fairly-critical GNOME applications broken in jhbuild for
half a month, due to a small dependency bump in one library beyond the
version of the library provided by jhbuild. I guess the maintainer was
not using jhbuild, so did not notice.

Breaks like this make it very hard for new contributors to get started
with GNOME development. I'm hoping that we can soon have an automated
system for detecting jhbuild build breaks, but we're not there yet, so
in the meantime we all have a shared responsibility to make sure new
contributors can build GNOME. Well, all contributors should be able to
build GNOME... but it's hardest for new contributors when jhbuild is
broken.

* Please be careful to never bump an external dependency of your module
without checking the jhbuild modulesets to ensure the new required
version is available. Edit the jhbuild moduleset appropriately if
needed. No need to get permission for this.

* Please be careful to never add new dependencies to your module
without also editing the jhbuild moduleset appropriately. It is
*always* wrong to add or remove a dependency for your module without
making a commit to jhbuild.

* If you want to add a dependency not already in GNOME, and you're not
sure if it's reasonable to add it to the jhbuild modulesets or where to
put it, please ask the release team for help.

My vision is that by making jhbuild more reliable, we can make it much
easier to contribute to GNOME. I'm tired of hearing stories from
interns about how difficult it is to get set up.

Thanks,

Michael