Code coverage should ignore files in .coveragerc

Start with .github/workflows/test-coverage.yml lines 31-35 and compare its coverage command with the exclusions in .coveragerc lines 1-2. Verify the GitHub Actions coverage run loads that configuration, then rerun the workflow or its coverage command and confirm excluded files no longer affect the total, targeting the reported 92% score.

I'm not sure why this is, but the code coverage I have running in a GitHub Action doesn't take my .coveragerc file into account. It should:

https://github.com/simonw/datasette/blob/cf7a2bdb404734910ec07abc7571351a2d934828/.github/workflows/test-coverage.yml#L31-L35

Here's the bit that's ignored:

https://github.com/simonw/datasette/blob/cf7a2bdb404734910ec07abc7571351a2d934828/.coveragerc#L1-L2

As a result my coverage score is 84%, when it should be 92%:

2020-06-13T21:41:18.4404252Z ----------- coverage: platform linux, python 3.8.3-final-0 -----------
2020-06-13T21:41:18.4404570Z Name                                 Stmts   Miss  Cover
2020-06-13T21:41:18.4404971Z --------------------------------------------------------
2020-06-13T21:41:18.4405227Z datasette/__init__.py                    3      0   100%
2020-06-13T21:41:18.4405441Z datasette/__main__.py                    3      3     0%
2020-06-13T21:41:18.4405668Z datasette/_version.py                  279    279     0%
2020-06-13T21:41:18.4405921Z datasette/actor_auth_cookie.py          20      0   100%
2020-06-13T21:41:18.4406135Z datasette/app.py                       499     27    95%
2020-06-13T21:41:18.4406343Z datasette/cli.py                       162     45    72%
2020-06-13T21:41:18.4406553Z datasette/database.py                  236     17    93%
2020-06-13T21:41:18.4406761Z datasette/default_permissions.py        40      0   100%
2020-06-13T21:41:18.4406975Z datasette/facets.py                    210     24    89%
2020-06-13T21:41:18.4407186Z datasette/filters.py                   122      7    94%
2020-06-13T21:41:18.4407394Z datasette/hookspecs.py                  34      0   100%
2020-06-13T21:41:18.4407600Z datasette/inspect.py                    36     23    36%
2020-06-13T21:41:18.4407807Z datasette/plugins.py                    34      6    82%
2020-06-13T21:41:18.4408014Z datasette/publish/__init__.py            0      0   100%
2020-06-13T21:41:18.4408240Z datasette/publish/cloudrun.py           57      2    96%
2020-06-13T21:41:18.4408786Z datasette/publish/common.py             19      1    95%
2020-06-13T21:41:18.4409029Z datasette/publish/heroku.py             97     13    87%
2020-06-13T21:41:18.4409243Z datasette/renderer.py                   63      4    94%
2020-06-13T21:41:18.4409450Z datasette/sql_functions.py               5      0   100%
2020-06-13T21:41:18.4410480Z datasette/tracer.py                     87     16    82%
2020-06-13T21:41:18.4410972Z datasette/utils/__init__.py            504     31    94%
2020-06-13T21:41:18.4411755Z datasette/utils/asgi.py                264     24    91%
2020-06-13T21:41:18.4412173Z datasette/utils/shutil_backport.py      44     44     0%
2020-06-13T21:41:18.4412822Z datasette/version.py                     4      0   100%
2020-06-13T21:41:18.4413562Z datasette/views/__init__.py              0      0   100%
2020-06-13T21:41:18.4414276Z datasette/views/base.py                288     19    93%
2020-06-13T21:41:18.4414579Z datasette/views/database.py            120      2    98%
2020-06-13T21:41:18.4414860Z datasette/views/index.py                57      2    96%
2020-06-13T21:41:18.4415379Z datasette/views/special.py              72     16    78%
2020-06-13T21:41:18.4418994Z datasette/views/table.py               418     18    96%
2020-06-13T21:41:18.4428811Z --------------------------------------------------------
2020-06-13T21:41:18.4430394Z TOTAL                                 3777    623    84%