Fix setup of linting GitHub Action.

Author: QuLogic

.github/workflows/reviewdog.yml

@@ -15,7 +15,7 @@ jobs:
           python-version: 3.8
 
       - name: Install flake8
-        run: pip3 install -r flake8
+        run: pip3 install flake8
 
       - name: Set up reviewdog
         run: |
@@ -30,6 +30,6 @@ jobs:
           REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           set -o pipefail
-          flake8 --docstring-convention=all | \
+          flake8 | \
             reviewdog -f=pep8 -name=flake8 \
               -tee -reporter=github-check -filter-mode nofilter