switch to using .flake8 config file

Author: JessicaS11

Diff for: .flake8

@@ -0,0 +1,9 @@
+[flake8]
+max_line_length = 88
+per-file-ignores = 
+    # too many leading '#' for block comment
+    test/*:E266
+    # line too long (several test strs)
+    test_granules.py:E501
+    # imported but unused
+    __init__.py:F401

Diff for: .github/workflows/linter_actions.yml

@@ -13,9 +13,7 @@ jobs:
       - name: Run black linter
         uses: psf/black@stable      
       # use the flake8 linter to annotate improperly formatted code
+      # note linter arguments are supplied via the .flake8 config file
       - name: Annotate PR after running flake8
         uses: TrueBrain/actions-flake8@v2
-        with:
-          max_line_length: 88
-          extra_arguments:
-            --per-file-ignores=__init__.py:F401 #test_granules.py:E501
+