[BPK-4282]: Rebase CRA 4 to BRS

Author: olliecurtis

packages/react-scripts/CHANGELOG.md

@@ -1,5 +1,17 @@
 # `backpack-react-scripts` Change Log
 
+## 9.0.0
+
+With this change its is only breaking due to the requirement of needing `Jest` to be upgraded to `26.6.0`, nothing else should affect from a consumer perspective.
+
+### Breaking
+
+- Rebased onto `upstream/master` v4.0.0 (ed958938f642007645dd5ac3466db36202f8754e).
+- This release rebases `backpack-react-scripts` on top of `create-react-app` v4! The major changes have been summarised in the following blog post:
+  [Create React App 4.0](https://github.com/facebook/create-react-app/blob/master/CHANGELOG.md#400-2020-10-23)
+
+- **The only breaking change is the requirement of Jest to be upgraded. Please follow [this guide](./migrating-from-v8-to-v9.md) when upgrading.**
+
 ## 8.0.5
 
 - Updated `bpk-mixins` to latest version

packages/react-scripts/README.md

@@ -1,12 +1,12 @@
 # backpack-react-scripts
 
-### **Important:** The currently supported version of **CRA** by `backpack-react-scripts` is up to `v3.4.1`. Versions above this will not work.
+### **Important:** The currently supported version of **CRA** by `backpack-react-scripts` is up to `v4.0.0`. Versions above this will not work.
 
 This package is a fork of [Create React App](https://github.com/facebookincubator/create-react-app) (specifically the
 `react-scripts` package). It's intended to be used in conjuction with `create-react-app` like so:
 
 ```sh
-npx create-react-app@3.4.1 my-app --scripts-version=@skyscanner/backpack-react-scripts --template @skyscanner/backpack --use-npm
+npx create-react-app@4.0.0 my-app --scripts-version=@skyscanner/backpack-react-scripts --template @skyscanner/backpack --use-npm
 
 # start your app development like you normally would with `create-react-app`
 cd my-app
@@ -32,63 +32,3 @@ npm start
   - `cssModules`: Boolean, true by default.
   - `sriEnabled`: Sets if SRI is to be used during build to add integrity hash for files, see [docs](https://github.com/waysact/webpack-subresource-integrity/blob/master/README.md).
     - **Note** if this is enabled, `crossOriginLoading` value is overriden with `anonymous` in order for it to output with the integrity value.
-
-## Releasing a new version of `backpack-react-scripts`
-
-1. To publish a new version of `backpack-react-scripts`, run the following command:
-
-   ```
-   npm run publish
-   ```
-
-2. You will be prompted to select a new semver version (MAJOR, MINOR, PATCH). Use the [CHANGELOG.md](./CHANGELOG.md) to decide on the nature of the changes since the last release.
-
-   - If you want to be extra careful, you can publish a prerelease by running this instead:
-
-   ```
-   npm run publish -- --canary
-   ```
-
-3. Update the [CHANGELOG.md](./CHANGELOG.md) with the new version, taking care to follow the format of previous releases.
-
-## Keeping this fork updated
-
-We wish to keep this fork updated with the upstream repo to benefit from the ongoing open source development
-of `create-react-app`. To keep this fork up to date, please follow the steps below:
-
-1. Ensure `master` is in sync with `upstream/master`:
-
-   ```sh
-   git checkout master
-   git remote add upstream [email protected]:facebook/create-react-app.git
-   git fetch upstream
-   git reset --hard upstream/master
-   git push --force-with-lease
-   ```
-
-1. Rebase `fork` on top of a **tagged release** on `master`:
-
-   ```sh
-   git checkout fork
-   git rebase <commit>
-   ```
-
-   > **Note:** `<commit>` should be the SHA-1 of the latest upstream release - _not_ the latest commit i.e. `upstream/master`
-
-1. Pair with someone else to fix any conflicts and cross examine changes in upstream with changes in our fork.
-
-   > This is the most time consuming part. Take care to make sure you are not regressing any functionality that we have added in our fork.
-
-1. Re-name your local, rebased `fork` branch to something else and push it to origin. This will ensure it runs through CI and you can verify your changes.
-
-   ```sh
-   git branch -m <branch>
-   git push origin <branch>
-   ```
-
-1. Finally, when we are confident that the rebase has been successful, re-name your branch back to `fork` and push it to origin:
-
-   ```sh
-   git branch -m fork
-   git push --force-with-lease
-   ```