Move flake8 test in new Lint GH Workflow thus before Provider tests (#1000)

* Move flake before provider tests

* Move flake8 to separate job

* Corrected run logic

.github/workflows/lint.yml

@@ -0,0 +1,36 @@
+name: Lint
+
+on:
+  push:
+    paths:
+      - '*.py'
+      - '!**.md'   
+  pull_request:
+    branches:
+      - master
+    paths:
+      - '*.py'  
+      - '!**.md'  
+  release:
+    types:
+      - released    
+
+jobs:
+  flake8_py3:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Python
+        uses: actions/setup-python@v1
+        with:
+          python-version: 3.7.4
+          architecture: x64
+      - name: Checkout PyTorch
+        uses: actions/checkout@master
+      - name: Install flake8
+        run: pip install flake8
+      - name: Run flake8
+        uses: suo/flake8-github-action@releases/v1
+        with:
+          checkName: 'flake8_py3'   # NOTE: this needs to be the same as the job name
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/main.yml

@@ -1,19 +1,14 @@
 name: Build
 
 on: 
-  push:
+  workflow_run:
+    workflows: ["Lint"]
+    types: [completed] 
     branches:
       - master
     paths-ignore:
       - '**.md'  
-  pull_request:
-    branches:
-      - master
-    paths-ignore:
-      - '**.md'  
-  release:
-    types:
-      - released
+  
 
 jobs:
   main:
@@ -105,8 +100,6 @@ jobs:
         pytest tests/test_util.py
         pytest tests/test_xarray_netcdf_provider.py
         pytest tests/test_xarray_zarr_provider.py
-    - name: run flake8 ⚙️
-      run: find . -type f -name "*.py" | xargs flake8
     - name: build docs 🏗️
       run: cd docs && make html
     - name: failed tests 🚩