Merge pull request #697 from rthalley/dependabot/pip/pytest-cov-tw-3.0.0

Update pytest-cov requirement from ^2.10.0 to ^3.0.0

diff --cc pyproject.toml
index 8e0b19a9c6abcf108a667be38e4147e9fb428119,291d6960e50e49f1b95ec3f8338cb225dc89b55e..64003450d3def6b7a5b3548942addcd55842f383
--- 1/pyproject.toml
--- 2/pyproject.toml
+++ b/pyproject.toml
@@@ -21,10 -21,10 +21,10 @@@ sniffio = {version="^1.1", optional=tru
  [tool.poetry.dev-dependencies]
  mypy = "^0.910"
  pytest = ">=5.4.1,<7"
- pytest-cov = "^2.10.0"
+ pytest-cov = "^3.0.0"
  flake8 = "^3.7.9"
  sphinx = "^4.0.0"
 -coverage = "^5.1"
 +coverage = "^6.0"
  twine = "^3.1.1"
  wheel = "^0.35.0"
  pylint = "^2.7.4"