v3.1.0

Features 🏗

Adds Enterprise Support to account creation process #233, closes #232:
- ADF will raise a ticket to add the account to an existing AWS support subscription when an account is created. As a prerequisite, your organization master account must already have enterprise support activated.
Adds nested deployment map support #266 and #328, closes #265:
- This enables usage of sub directories within the deployment_maps folder.

Fixes specific role usage to be used in Build and Deploy only #295.
Corrects removing pipelines anchor in docs #279.
Fixes CI builds due to isort version mismatch #284.
Fixes error handling of generate_params intrinsic upload function #277, closes #276.
Fixes spec_inline attribute of CodeBuild in docs #289.
Fixes provider spec_inline support of CodeBuild in #293.
Fixes supported list of intrinsic upload path styles, enables usage of s3-url and s3-key-only #275, closes #299.
Fixes create deployment account concurrency failure #287, closes #280.
Fixes approval stage usage, by limiting specific role usage to Build and Deploy steps #295.
Fixes yarnpkg GPG #313, closes #325.
Removes dependency on botocore.vendored.requests #326, closes #324.

Improves docs on providers and their properties #274.
Separates pipeline cleanup from input generation script #288.
Upgrades Python from v3.7 to v3.8 #313.
Upgrades CodeBuild image from "aws/codebuild/standard:2.0" to "aws/codebuild/standard:5.0" #313, closes #267, closes #300.
Upgrades CDK from v1.32 to v1.88 #313, closes #292.

Many thanks to our community for driving this release. And special thanks to @StewartW for contributing new features to ADF!