Remove Heroku deployment

.github/workflows/heroku.yml

@@ -1,16 +0,0 @@
-name: Deploy to Heroku
-
-on:
-  push:
-    branches: [ main ]
-
-jobs:
-  deploy:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-    - uses: akhileshns/heroku-deploy@v3.8.9
-      with:
-        heroku_api_key: ${{secrets.HEROKU_API_KEY}}
-        heroku_app_name: streamlit-webrtc-example
-        heroku_email: ${{ secrets.HEROKU_EMAIL }}

Aptfile

@@ -1 +0,0 @@
-libgl1

Procfile

@@ -1 +0,0 @@
-web: streamlit run --server.port $PORT app.py

README.md

@@ -1,8 +1,6 @@
 # streamlit-webrtc-example
 
-Hosted on Streamlit Cloud: [![Open in Streamlit](https://static.streamlit.io/badges/streamlit_badge_black_white.svg)](https://share.streamlit.io/whitphx/streamlit-webrtc-example/main/app.py) https://share.streamlit.io/whitphx/streamlit-webrtc-example/main/app.py 
-
-Hosted on Heroku: https://streamlit-webrtc-example.herokuapp.com/
+Hosted on Streamlit Cloud: [![Open in Streamlit](https://static.streamlit.io/badges/streamlit_badge_black_white.svg)](https://share.streamlit.io/whitphx/streamlit-webrtc-example/main/app.py) https://share.streamlit.io/whitphx/streamlit-webrtc-example/main/app.py
 
 [![ko-fi](https://ko-fi.com/img/githubbutton_sm.svg)](https://ko-fi.com/D1D2ERWFG)
 
@@ -12,38 +10,4 @@ Hosted on Heroku: https://streamlit-webrtc-example.herokuapp.com/
 
 ## Deployment notes
 
-The deployment to Heroku is automated with GitHub actions: [./.github/workflows/heroku.yml](./.github/workflows/heroku.yml).
-
 [Streamlit Cloud](https://streamlit.io/cloud) automatically triggers the deployment on its CI/CD.
-
-## Manual deployment to heroku
-### Prerequisites
-1. Set up `heroku` command.
-
-2. Add [`heroku-buildpack-apt`](https://github.com/heroku/heroku-buildpack-apt) to buildpacks.
-   ```shell
-   $ heroku buildpacks:add --index 1 heroku-community/apt
-   ```
-
-   See
-   https://help.heroku.com/IYRYW6VB/how-do-i-install-additional-software-packages-that-my-application-requires
-   and
-   https://github.com/heroku/heroku-buildpack-apt
-   for details.
-
-### Deploy
-#### If dependencies have changed, update `requirements.txt`
-1. Update `requirements.txt`.
-   ```shell
-   $ make deps/update
-   ```
-
-2. Commit it.
-   ```shell
-   $ git add requirements.txt
-   $ git commit -m "requirements.txt"
-   ```
-#### Deploy the current branch to Heroku
-```shell
-$ git push heroku <current-branch>:main
-```