Support for PostgreSQL 13 and 14

Changelog:

• Release new version 2.0
• Add support for PostgreSQL 13 and 14
• Updated Docker image with PostgreSQL 14

In depth:

• Upgrade google dependenciesL
  • oogle-cloud-bigquery==3.2.0
  • google-auth==2.8.0
  • google-auth-oauthlib==0.5.2
• Replace https://github.com/gabfl/Multicorn with https://github.com/pgsql-io/multicorn2 to add support for PostgreSQL 13 and 14