[CI/linting]: Change trigger and flake8 output

Fixes #443

.github/workflows/linting.yml

@@ -1,44 +1,22 @@
 name: Linting
 
-on: [push,pull_request]
+on: 
+  push:
+    branches:
+      - master
+  pull_request:
 
 jobs:
-  precheck:
-    runs-on: ubuntu-20.04
-
-    outputs:
-      should_skip: ${{ steps.skip_check.outputs.should_skip }}
-    steps:
-      - id: skip_check
-        uses: fkirc/skip-duplicate-actions@master
-        with:
-          # skip concurrent jobs if they are on the same thing
-          concurrent_skipping: 'same_content'
-          # never skip PR + manual/scheduled runs
-          do_not_skip: '["pull_request", "workflow_dispatch", "schedule"]'
-
   flake8:
-    needs: precheck
+    runs-on: ubuntu-latest
-    if: ${{ needs.precheck.outputs.should_skip != 'true' }}
-    runs-on: ubuntu-20.04
-
-    strategy:
-      matrix:
-        python-version: ["3.9", "3.10"]
-
     steps:
       - uses: actions/checkout@master
       - name: Setup Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v3
         with:
-          python-version: ${{ matrix.python-version }}
+          python-version: "3.9"
           architecture: x64
       - name: Install flake8
         run: pip install flake8
       - name: Run flake8
-        uses: suo/flake8-github-action@releases/v1
+        run: flake8 --format='::error title=flake8,file=%(path)s,line=%(row)d,col=%(col)d::[%(code)s] %(text)s'
-        with:
-          checkName: 'flake8'   # NOTE: this needs to be the same as the job name
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-