title: Github Workflow can't install python packages from requirements.txt
body: <p>I am trying to build a docker image every time when someone commits to the &quot;main&quot; branch. I want to install my packages from my <code>requirements.txt</code>. When I build the image local everything works fine, but when my pipeline in Github tries to build it I get the following error:</p>
  <p><code>Error: buildx failed with: error: failed to solve: process &quot;/bin/sh -c pip install -r requirements.txt&quot; did not complete successfully: exit code: 1</code></p>
  <p>My Dockerfile looks like:</p>
  <pre><code>RUN mkdir /usr/src/app/
  COPY .. /usr/src/app/
  WORKDIR /usr/src/app/
  EXPOSE 8080
  COPY . .
  RUN pip install -r requirements.txt
  CMD [&quot;python&quot;, &quot;app.py&quot;]
  </code></pre>
  <p>The directory structure is:</p>
  <p><a href="https://i.stack.imgur.com/rEEu8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rEEu8.png" alt="structure" /></a></p>
  <p>And the Github yaml:</p>
  <pre><code>name: Docker-Image CI/CD
  
  on:
    push:
      branches:
        - 'main'
  
  jobs:
    build:
      runs-on: ubuntu-latest
  
      steps:
        -
          name: Checkout 
          uses: actions/checkout@v2
        -
          name: Login to Docker Hub
          uses: docker/login-action@v1
          with:
            username: ${{ secrets.DOCKER_HUB_USERNAME }}
            password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
        -
          name: Set up Docker Buildx
          uses: docker/setup-buildx-action@v1
        -
          name: Build and push
          uses: docker/build-push-action@v2
          with:
            context: .
            file: ./flask_web/Dockerfile
            push: true
            tags: ${{ secrets.DOCKER_HUB_USERNAME }}/dbdashboard:latest
  </code></pre>
  <p>I really don't understand where the problem is. Installing the packages manually via <code>pip install Flask</code> in the Dockerfile works.</p>