Trouble using Google Maps API in Heroku hosted Ionic app

I am hosting my Ionic app in Heroku and I’ve made almost all the necessary changes to give my PWA the same features as a hybrid app. However, I have trouble using the Google Maps API on Heroku. The reason for this issue is that my Heroku app does not start with https (it starts with http), and if I use either http or https on the Maps API, I get errors.

If I use https, I get: “Only secure origins are allowed”, since the Heroku app is not secure.
If I use http, I get: "Mixed Content: The page at ‘MY URL’ was loaded over HTTPS, but requested an insecure resource ".

Is there a way to make my Heroku app secure or another way to use the Google Maps API?

Thanks in advance.