Use upsert = true by default when installing

[carolynvs]

Someone should be able to repeat the install action of a bundle when it fails and have it properly handle when that step has been executed already.

For example, if I have a bundle with 2 steps: first it runs helm install and then it does something else, and the second step fails, I'm going to repeat the install command to get the second step to pass. If upsert isn't specified, then the bundle will fail because the release already exists.

Another scenario is a bundle author is iterating on their bundle and adding new stuff to it, and then re-running it. They should be able to repeat install over and over, and have it apply the newest changes to the bundle, without complaining that the release already exists.

By default, mixins should handle situations like this gracefully. One way to do that is to have upsert = true set. Another is more complicated, but I think #17 suggests checking if the release exists and is the same. I think that scenario requires a lot more work to make sure that nothing has changed (such as the chart is the same but a value is different). So this would be a good start.

[MChorfa]

Fixed in v0.1.14