The add_vline function uses recently-added features in the underlying rendering engine, Plotly.js, meaning you need a recent version of Plotly.js wherever you are using Plotly.py. In practice this means installing the latest jupyterlab-plotly extension in JupyterLab, the latest dash/dash_core_components in Dash, or waiting until VSCode and/or Streamlit update their onboard copies of Plotly.js, if you’re seeing this problem in those environments.
More information can be found here: Troubleshooting | Python | Plotly