fix requirements installation

Author: vuillaut

action.yml

@@ -31,11 +31,11 @@ runs:
         python-version: '3.x'
 
     - name: Install deps
-      run: python -m pip install -r requirements.txt
+      run: python -m pip install -r ${{ github.action_path }}/requirements.txt
       shell: bash
 
     - name: Run check script
-      run: python check_contributors.py
+      run: python ${{ github.action_path }}/check_contributors.py
       shell: bash
       env:
         ACTION_MODE: ${{ inputs.mode }}