PgBouncer: WARNING DNS lookup failed: host.docker.internal: result=0

If you're using PgBouncer in a Docker container and try to connect to the host via host.docker.internal, you may experience this error:

2020-06-15 17:23:46.211 UTC [1] WARNING DNS lookup failed: host.docker.internal: result=0

This fix resolves it: Fix DNS for Docker #8