Migrate coverage configuration to pyproject

We also remove an incorrect note from tox.ini: coverage configuration is
not the same as running coverage.

Change-Id: I62305fbfdaaa50040b05545fa40426f4c9fadae8
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

pyproject.toml

@@ -115,6 +115,15 @@ skip = "*.po,*.js,*.css,*.html,*.svg,HACKING.py,*hacking*,*build*,*_static*,doc/
 count = true
 quiet-level = 4
 
+[tool.coverage.run]
+branch = true
+source = ["nova"]
+omit = ["nova/tests/*"]
+concurrency = ["eventlet"]
+
+[tool.coverage.report]
+ignore_errors = true
+
 [tool.mypy]
 python_version = "3.10"
 show_column_numbers = true