Set up CI for the PUDL data catalog repo

[zaneselvans]

We have a nominally working PUDL Intake Catalog! And now it needs to be tested.

• [x] Flesh out the README
  • [x] link to Intake examples, talks
  • [x] link to CarbonPlan repo for additional examples
  • [x] link to Pangeo Forge as another example
  • [x] Link to any Intake issues in the main PUDL repository
  • [x] Outline the flow of data from PUDL to the data catalog through CI/CD processes.
  • [x] Add CI status, CodeCov, PyPi, conda-forge, python version compatibility, and black badges to README
  • [x] Add Catalyst contact info from template repo
  • [x] Convert README to RST
  • [x] Add code of conduct from template repo
• [x] Set up Tox to run linters, pytest, and generate test coverage
• [x] Create a GitHub action to run Tox automatically
• [x] Set up dependabot to update dependencies
• [x] Define a Python (conda?) environment for the data catalog repo
• [x] Test that pudl_catalog.yaml is valid
• [x] Create a dev branch
• [x] Make sure that pre-commit.ci is set up and working on the repository
• [x] Set up tests to work without storing data in the repository
• [x] Test that a small amount of data (e.g. 2020 Idaho):
  • [x] can be read from monolithic & partitioned versions of the remote data.
  • [x] is available from gcs:// and https:// URLs
  • [x] is identical whether we get it from Intake or via pd.read_parquet()
• [x] Set up CodeCov to receive coverage reports and track test coverage over time