In the newest version of the Penneo web interface, you manage your API keys from your user profile settings.
You can find an article explaining the User Profile settings here.
- Click on the profile icon in the upper right corner
- Click on "My account" in the dropdown menu
- Choose the tab "API integration"
- Below the Client Key and Password there is a red button with the text "Reset keys", click on it to create a new integration key.