Mypy-boto3

Fixed
- `[services]` All methods generated from botocore shapes are now keyword-only
- `[botocore-stubs]` incorrect annotations for `botocore.exceptions.ClientError`

Fixed
- `[cloudformation]` added a temporary fix for `ResourceStatusType` literal

Added
- `[services]` added [Proton](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/proton.html) service support

Changed
- `[docs]` Keyword-only method arguments are marked correctly in documentation

Fixed
- `[botocore-stubs]` fixed `ClientError` type annotation

Changed
- `[boto3-stubs]` now depend on `botocore-stubs`
- `[botocore-stubs]` all exceptions kwargs are annotated properly

Fixed
- `[botocore-stubs]` all files formatted with `black`/`isort`
- `[botocore-stubs]` improved `BaseClient` annotations
- `[botocore-stubs]` improved `ServiceModel` annotations
- `[botocore-stubs]` improved `WaiterModel` annotations

Notes

Starting from this release, the builder also generates `botocore-stubs` package.

Added
- `[docs]` new MarkDown processor with faster ToC generation
- `[botocore-stubs]` initial release

Changed
- `[builder]` removed platform-specific dependencies

Fixed
- `[services]` `Client` and `Resource` methods with one or two arguments are no longer keyword-only
- `[services]` keyword-only flag did not work for collections
- `[docs]` PyPI-compatible markdown links point to header instead of a content