Add pre-release test to CI [melodic-devel]

[tylerjw]

This adds the pre-release test to the melodic-devel branch. Since this is a release branch I believe adding it to all PRs made against this branch will be useful.

[v4hn]

Since this is a release branch I believe adding it to all PRs made against this branch will be useful.

Doing prerelease tests automatically for PRs would be a lot of overhead I don't like.
Running it for pushed commits is debatable, but might make sense. This repo sees few commits (in contrast to moveit).

master is a "release branch" as well, because we use it as the base for noetic releases. So whatever the decision I don't see why we should differentiate between the two branches.

[tylerjw]

I updated this so it works just like the one on master now. The pre-release test for this repo only takes ~10min and it is nice being able to see if it is passing when going to the repo.

[tylerjw]

Per @rhaschke comment in the master branch version of this PR I also updated this to test moveit as a downstream dependency as part of the pre-release test.

[tylerjw]

Pushed the same changes here as I made on the PR for master.

[rhaschke]

Let's finish master first (#70) and then apply the same changes here.
Nevertheless, I triggered a release to fix upstream issues: ros/rosdistro#29385
(I was confused that we had release tags 0.7.3 and 0.8.0, but no release yet.)

[vatanaksoytezer]

Closing since this is merged with #83.