Upgrade project to support dbt 0.1.x

[clausherther]

Updates the following files to support dbt==0.1.x

• .gitignore
• dbt_project.yml
• packages.yml
• integration_tests/dbt_project.yml

[clausherther]

cc: @joellabes

[joellabes]

Looks good! My only nitpick is that it'd be nice to also (and probably first) release a 0.4.2 patch which allows dbt [">=0.20.0", "<1.1.0"] - there's one breaking change in dbt-utils 0.8.0, and if people aren't able to move to that I'd like them to still be able to get onto Core 1.0.

[clausherther]

@joellabes thinking about this some more: while I agree that'd be nice, I don't think I'll have the brainspace this week to handle the resulting doubled-up package dependencies between a patch for dbt-date and dbt-expectations, in addition to the already too tightly linked main branches.
Actually I think what you're saying is do the 0.4.2 release first, and a 0.4.7 release on dbt-exp, then a second set of PRs for 0.5.0 on both. I think that'll work. I just didn't want to maintain an old branch.