Prepare version 4's details for README and MIGRATION; sunset <= 3

MIGRATION.md

@@ -1,11 +1,15 @@
 # Migration Guide
 
-Pa11y's API changes between major versions. This is a guide to help you make the switch when this happens.
+This package's API and/or supported set of environments changes between major versions. This is a guide to help you update your project to use a new major version.
 
-## Migrating from 2.x to 3.x
+## Migrating to 4 from 3
 
-Pa11y Webservice Client 3.x only supports Node.js v12 and higher, you'll need to upgrade to be able to use it.
+Versions 4.x of this client require Node.js version 14 or above.
 
-## Migrating from 1.x to 2.x
+## Migrating to 3 from 2
 
-Pa11y Webservice Client 2.x only supports Node.js v8.0.0 and higher, you'll need to upgrade to be able to use it.
+Versions 3.x of this client require Node.js version 12 or above.
+
+## Migrating to 2 from 1
+
+Versions 2.x of this client require Node.js version 8 or above.

README.md

@@ -159,8 +159,9 @@ The following table lists the major versions available and, for each previous ma
 
 | :grey_question: | Major Version | Last Release | Node.js Required | Support Ends     |
 | :-------------- | :------------ | :----------- | :--------------- | :--------------- |
-| :heart:         | 3             | N/A          | 12+              | N/A              |
-| :hourglass:     | 2             | 2.0.0        | 8+               | 2022-05-26       |
+| :heart:         | 4             | 4.0.0        | 14+              | Current major version |
+| :hourglass:     | 3             | 3.0.0        | 12+              | 2023-11-01       |
+| :skull:         | 2             | 2.0.0        | 8+               | 2022-05-26       |
 | :skull:         | 1             | 1.2.1        | 0.10+            | 2020-01-05       |
 
 ## License