add snowflake

[emmyoop]

resolves #200

This is a:

• documentation update
• bug fix with no breaking changes
• new functionality
• a breaking change

All pull requests from community contributors should target the main branch (default).

Description & motivation

This adds support for running integration tests against dbt-snowflake.

Checklist

• This code is associated with an issue which has been triaged and accepted for development.
• I have verified that these changes work locally
• I have updated the README.md (if applicable)
• I have added tests & descriptions to my models (and macros if applicable)
• I have added an entry to CHANGELOG.md

[emmyoop]

redshift and bigquery both get database permission issues with creating a new schema

  Access Denied: Table dbt-test-env:codegen_integration_tests__data_source_schema.codegen_integration_tests__data_source_table: Permission bigquery.tables.delete denied on table dbt-test-env:codegen_integration_tests__data_source_schema.codegen_integration_tests__data_source_table (or it may not exist).

That's why I've only added snowflake here.