[v2] PR docs (#5933)

* Document pull request policy during v2 betas

* Update edit link

* Update README.md

* Add branch instructions to contributing guide

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,12 @@
+<!--
+  Please choose the correct branch for your pull request:
+
+  * `master` branch for Gatsby version 2 bug fixes
+  * `master` branch for any new features (these will be released in the Gatsby v2 betas)
+  * `v1` branch for updates to the `www` and `docs` directories
+  * `v1` branch for Gatsby version 1 bug fixes
+
+  Note: We will *not* accept new features for Gatsby v1, only bug fixes, documentation and updates to gatsbyjs.org.
+
+  Learn more about contributing: https://www.gatsbyjs.org/docs/how-to-contribute/
+-->

README.md

@@ -12,11 +12,23 @@
 
 ⚛️📄🚀 Blazing-fast site generator for React
 
-**NOTE:** This branch is the beta version of Gatsby V2. You can find documentation at [v2--gatsbyjs.netlify.com/](https://v2--gatsbyjs.netlify.com/). (TODO: update this URL once the `next` subdomain is ready.)
+**NOTE:** This branch is the beta version of Gatsby V2. You can find documentation at [next.gatsbyjs.org](https://next.gatsbyjs.org/).
 
 For `gatsby@1`, please see [the v1 branch](https://github.com/gatsbyjs/gatsby/tree/v1).
 
-**Are you using V1? Check out [our V1 => V2 migration guide](https://v2--gatsbyjs.netlify.com/docs/migrating-from-v1-to-v2/).** (TODO: update this URL once the `next` subdomain is ready.)
+**Are you using V1 and want to try upgrading and help prepare Gatsby for v2? Check out [our V1 => V2 migration guide](https://next.gatsbyjs.org//docs/migrating-from-v1-to-v2/).**
+
+**How are pull requests being handled during the v2 beta?**
+
+The following policy will be in place during the v2 beta:
+
+- We will only accept _bug fixes_ for Gatsby v1. Any PRs opened against v1 that are not bug fixes will be closed
+
+- If the bug fix is applicable to v2, we will open an additional issue to track porting the change to v2
+
+- All _new features_ should be opened as pull requests against v2 (the `master` branch)
+
+We're using this policy as the Gatsby team currently spends a significant amount of time maintaining two active branches - the v1 branch and the v2 branch - we'd like to limit this work to focus on getting v2 released and start working on oft-requested new features like schema snapshots and schema stitching.
 
 ## Showcase
 

docs/docs/how-to-contribute.md

@@ -31,6 +31,18 @@ If you create a loader or plugin, we would <3 for you to open source it and put
 Gatsby uses a "monorepo" pattern to manage its many dependencies and relies on
 lerna and yarn to configure the repository for active development.
 
+We're currently gearing up to release a new major version, v2.
+
+During this time, please choose the correct branch for your pull request:
+
+* `master` branch for Gatsby version 2 bug fixes `master` branch for any new
+* features (these will be released in the Gatsby v2 betas) `v1` branch for
+* updates to the `www` and `docs` directories `v1` branch for Gatsby version
+* 1 bug fixes
+
+Note: We will *not* accept new features for Gatsby v1, only bug fixes,
+documentation and updates to gatsbyjs.org.
+
 You can install the latest version of Gatsby by following these steps:
 
 - Clone the repo, navigate to its directory.

docs/docs/migrating-from-v1-to-v2.md

@@ -2,7 +2,7 @@
 title: Migrating from v1 to v2
 ---
 
-> This document is a work in progress. Have you upgraded your site and run into something that's not covered here? [Add your changes on GitHub](https://github.com/gatsbyjs/gatsby/edit/v2/docs/docs/migrating-from-v1-to-v2.md)!
+> This document is a work in progress. Have you upgraded your site and run into something that's not covered here? [Add your changes on GitHub](https://github.com/gatsbyjs/gatsby/edit/master/docs/docs/migrating-from-v1-to-v2.md)!
 
 ## Introduction