Add releasing docs to README (#86)

* Update README.md

* add bump dbt-core and dbt-adapters step to readme

* add adapter implementations to releasing docs

README.md

@@ -1,7 +1,22 @@
-## Understanding dbt-common
+## dbt-common
 
 The shared common utilities for dbt-core and adapter implementations use
 
+### Releasing dbt-common
+To release a new version of dbt-common to pypi, you'll need to: 
+1. Bump the `version` in [dbt_common_/__about__.py](https://github.com/dbt-labs/dbt-common/blob/main/dbt_common/__about__.py)
+2. Run the [release workflow](https://github.com/dbt-labs/dbt-common/actions/workflows/release.yml) to test pypi and confirm a successful test release in: https://test.pypi.org/project/dbt-common/
+3. Run the [release workflow](https://github.com/dbt-labs/dbt-common/actions/workflows/release.yml) to prod pypi and confirm a successful release in: https://pypi.org/project/dbt-common/
+4. Bump the version of `dbt-common` in `dbt-core` and `dbt-adapters` if you're releasing a new major version or a pre-release: 
+   * `dbt-core`: [setup.py](https://github.com/dbt-labs/dbt-core/blob/main/core/setup.py)
+   * `dbt-adapters`: [pyproject.toml](https://github.com/dbt-labs/dbt-adapters/blob/main/pyproject.toml)
+   * Adapter Implementations: 
+     * `dbt-postgres`: [pyproject.toml](https://github.com/dbt-labs/dbt-postgres/blob/main/pyproject.toml)
+     * `dbt-snowflake`: [setup.py](https://github.com/dbt-labs/dbt-snowflake/blob/main/setup.py)
+     * `dbt-bigquery`: [setup.py](https://github.com/dbt-labs/dbt-bigquery/blob/main/setup.py)
+     * `dbt-redshift`: [setup.py](https://github.com/dbt-labs/dbt-redshift/blob/main/setup.py)
+     * `dbt-spark`: [setup.py](https://github.com/dbt-labs/dbt-spark/blob/main/setup.py)
+
 ## Getting started
 
 - [Install dbt](https://docs.getdbt.com/docs/get-started/installation)