use flake8 config file rather than command line flag

.flake8

@@ -0,0 +1,2 @@
+[flake8]
+builtins=_

.github/workflows/binary-applications.yml

@@ -22,9 +22,9 @@ jobs:
             - name: Lint with flake8
               run: |
                 # stop the build if there are Python syntax errors or undefined names
-                python -m flake8 src --count --select=E9,F63,F7,F82 --builtins=_ --show-source --statistics
+                python -m flake8 src --count --select=E9,F63,F7,F82 --show-source --statistics
                 # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-                python -m flake8 src --count --builtins=_ --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+                python -m flake8 src --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
 
     build-windows-binaries:
         name: "Build windows binaries"

.github/workflows/build-and-test.yml

@@ -30,9 +30,9 @@ jobs:
             - name: Lint with flake8
               run: |
                 # stop the build if there are Python syntax errors or undefined names
-                python -m flake8 src --count --select=E9,F63,F7,F82 --builtins=_ --show-source --statistics
+                python -m flake8 src --count --select=E9,F63,F7,F82 --show-source --statistics
                 # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-                python -m flake8 src --count --builtins=_ --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+                python -m flake8 src --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
 
     run-model-tests:
         name: "Run model tests"

HISTORY.rst

@@ -36,8 +36,8 @@
 
 
 
-Unreleased Changes
+Unreleased Changes (3.10)
-------------------
+-------------------------
 * General:
     * Add a ``--language`` argument to the command-line interface, which will
       translate model names, specs, and validation messages.