Stop using pytest-flake8

.github/workflows/build.yaml

@@ -70,8 +70,7 @@ jobs:
         shell: bash -l {0}
         run: |
           conda install -y -q \
-            "flake8<5" \
-            pytest pytest-flake8 pytest-xdist pytest-openfiles pytest-cov
+            pytest pytest-xdist pytest-openfiles pytest-cov
 
       - name: List installed packages
         shell: bash -l {0}

pyproject.toml

@@ -41,8 +41,6 @@ dynamic = ["version"]
 postgres = ["psycopg2"]
 test = [
     "pytest >= 3.2",
-    "flake8 >= 3.7.5",
-    "pytest-flake8 >= 1.0.4",
     "pytest-openfiles >= 0.5.0",
     "numpy >= 1.17",
     "matplotlib >= 3.0.3",
@@ -126,8 +124,6 @@ line_length = 110
 write_to = "python/lsst/daf/butler/version.py"
 
 [tool.pytest.ini_options]
-addopts = "--flake8"
-flake8-ignore = ["W503", "E203", "N802", "N803", "N806", "N812", "N815", "N816"]
 # The matplotlib test may not release font files.
 # Some unit tests open registry database in setUpClass.
 open_files_ignore = ["*.ttf", "gen3.sqlite3"]