Add flake8 CI

Author: lkuchenb

.flake8

@@ -0,0 +1,30 @@
+[flake8]
+ignore=
+    #E124 closing bracket does not match visual indentation
+    E124,
+    #E127 continuation line over-indented for visual indent
+    E127,
+    #E128 continuation line under-indented for visual indent
+    E128,
+    #E201 whitespace after
+    E201,
+    #E202 whitespace before
+    E202,
+    #E203 whitespace before
+    E203,
+    #E221 multiple spaces before operator
+    E221,
+    #E222 multiple spaces after operator
+    E222,
+    #E251 unexpected spaces around keyword / parameter equals
+    E251,
+    #E271 multiple spaces after keyword
+    E271,
+    #E501 line too long
+    E501,
+    #E123 closing bracket does not match indentation of opening bracket's line
+    E123,
+    #E126 continuation line over-indented for hanging indent
+    E126,
+    #W503 line break before binary operator [PEP8 recomments this style]
+    W503

.github/workflows/flake8.yaml

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+name: Check code with flake8
+
+on:
+  pull_request:
+    branches: [ main, develop ]
+
+jobs:
+  flake8:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set conda package directory
+      run: |
+        mkdir /tmp/condapkgs
+        echo "CONDA_PKGS_DIRS=/tmp/condapkgs" >> $GITHUB_ENV
+    - name: Set up Python 3.8
+      run: |
+        $CONDA/bin/conda create -p /tmp/condaenv python=='3.8.*' flake8
+    - name: Activate conda environment
+      run: |
+        echo "/tmp/condaenv/bin" >> $GITHUB_PATH
+        export PATH="/tmp/condaenv/bin:$PATH"
+    - name: Run flake8
+      run: |
+        flake8