Release Autoproj 2.9.0 / Autobuild 1.17.0 · rock-core/autoproj

Important notes:

automated build environments must add the apt_dpkg_update flag to their seed config. This flag controls automatic APT package update, see details in the new features below.

Git imports can now refer to remote branches that are not under refs/heads/, for instance refs/pull//head on GitHub:
```
- type: git
  branch: refs/pull/205/head
```
Autoproj now complains about Git-LFS being missing only for packages that have it enabled
Optionally update APT packages instead of only checking for their presence. There's a new question to enable/disable this feature at bootstrap time (or on upgrade to 2.9.0)
Add the ability to install new repository to the system's package manager (for now only APT is supported). See this documentation for more details

fix status --local
fix -k to continue even if an update fails
the pip system package should now be automatically installed when pip packages are required
fixed handling of gems missing in the workspace if they are directly selected by the manifest (as opposition to being depended-upon by other packages). This was triggered by partial update/build (e.g. autoproj update <PACKAGE>)

autoproj is now exporting a JSON file to report on what was done during the last build, in .autoproj/build_reprot.json. This can be used in e.g. CI builds to report on what had been done.
fixed computed package dependencies in post-update hooks when no packages are selected (e.g. autoproj update --config)