feat(functions): PostgreSQL Python example

[redanrd]

Summary

This example shows a serverless function in Python to connect to PosgreSQL database.

Checklist

• I have reviewed this myself.
• I have attached a README to my example. You can use this template as reference.
• I have updated the project README to link my example.

[cyclimse]

Suggested change

	PG_HOST=os.environ.get('PG_HOST')
	PG_USER=os.environ.get('PG_USER')
	PG_DATABASE=os.environ.get('PG_DATABASE')
	PG_PASSWORD=os.environ.get('PG_PASSWORD')
	PG_PORT=os.environ.get('PG_PORT')
	PG_SSL_ROOT_CERT=os.environ.get('PG_SSL_ROOT_CERT')
	PG_HOST=os.environ["PG_HOST"]
	PG_USER=os.environ["PG_USER"]
	PG_DATABASE=os.environ["PG_DATABASE"]
	PG_PASSWORD=os.environ["PG_PASSWORD"]
	PG_PORT=os.environ["'PG_PORT"]
	PG_SSL_ROOT_CERT=os.environ["PG_SSL_ROOT_CERT"]

I prefer os.getenv instead of os.environ.get. But because here those env vars are required, it's even better to catch the error early.