Merge pull request #362 from michael-ciniawsky/pr_template

chore(PR_TEMPLATE): update link to writer's guide

Author: bebraw

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,4 +1,4 @@
 1. [Read and sign the CLA](https://cla.js.foundation/webpack/webpack.js.org). This needs to be done only once. PRs that haven't signed it won't be accepted.
-2. Make sure your PR complies with [the writer's guide](https://webpack.js.org/writers-guide/).
+2. Check out the [development guide](https://webpack.js.org/development/) for the API and development guidelines.
 3. Read through the PR diff carefully as sometimes this can reveal issues. The work will be reviewed, but this can save some effort.
 4. Remove these instructions from your PR as they are for your eyes only.