How to automate expo upload:android

Hello! It's me again 😄

### Topic and scope of discussion
How would you pass service account JSON to `expo upload:android`?

### Motivation
I want to create a manually triggered Github action to automate uploads to Play Store?

### Additional context
`expo upload:android` requires the `--path` to the JSON file containing the service account. I dug into the expo-cli code and they use fs.readFile to get the content so not sure how to make it available inside the Github actions. Do you know a way to provide it?