fix: implement v3 deprecations

- interfaces marked as deprecated through v2 should now result in a TaskConfigurationError
- update readme to remove references to deprecations

docs/RELEASE-NOTES-V2.md

@@ -0,0 +1,38 @@
+
+# simple-git release 2.x
+
+Released on [28 April 2020](https://github.com/steveukx/git-js/tree/v2.0.0)
+
+Major release 2.x changes the way the queue of tasks are handled to use promises internally and makes
+available the `.then` and `.catch` methods for integrating with promise consumers or async await.
+
+TypeScript is used by default for all new code, allowing for auto-generated type definitions and a phased
+re-write of the library rather than a big-bang.
+
+For a per-release overview of changes, see the [changelog](https://github.com/steveukx/git-js/blob/main/simple-git/CHANGELOG.md).
+
+## 2.x Upgrade Notes
+
+When upgrading to release 2.x from 1.x, see the [changelog](https://github.com/steveukx/git-js/blob/main/simple-git/CHANGELOG.md) for the release 2.0.0
+
+# Altered APIs
+
+- ~~2.25.0 depends on Node.js version 12 or above, for use in lower versions of node.js ensure you are also
+  importing the necessary polyfills from `core-js`, see [Legacy Node Versions](https://github.com/steveukx/git-js/blob/main/docs/LEGACY_NODE_VERSIONS.md)~~
+  _this change has been reverted in 2.30.0 and will be postponed until version 3.x_.
+
+- 2.13.0 `.push` now returns a [PushResult](https://github.com/steveukx/git-js/blob/main/simple-git/typings/response.d.ts) parsed representation of the response.
+
+- 2.11.0 treats tasks chained together as atomic, where any failure in the chain prevents later tasks from
+  executing and tasks called from the root `git` instance as the origin of a new chain, and able to be
+  [run in parallel](#concurrent--parallel-requests) without failures impacting one anther. Prior to this
+  version, tasks called on the root `git` instance would be cancelled when another one failed.
+
+- 2.7.0 deprecates use of `.silent()` in favour of using the `debug` library - see the
+  [debug logging guide](https://github.com/steveukx/git-js/blob/main/docs/DEBUG-LOGGING-GUIDE.md) for further details.
+
+- 2.6.0 introduced `.then` and `.catch` as a way to chain a promise onto the current step of the chain.
+  Importing from `simple-git/promise` instead of just `simple-git` is no longer required and is actively discouraged.
+
+For the full history see the [changelog](https://github.com/steveukx/git-js/blob/main/simple-git/CHANGELOG.md);  
+