Update npm version scripts to manage new releases branch

This updates the `postversion.sh` script to merge master into the new
`releases` branch and then copy and commit the version archives there,
instead of into master, so that the archives aren't cluttering up the
master branch unnecessarily.

RELEASE.md

@@ -9,9 +9,9 @@ The release process is mostly automated, here is a brief overview of the steps
    - Updates `AUTHORS`
    - Updates `package.json` with new version
    - Creates a new git tag
-   - Copies new release documentation into place in `docs/_releases/`, using the new release id
 2. `npm publish` publishes the new release to the npm registry
 3. `git push origin --follow-tags` pushes the changes to GitHub
+4. Archive the new release in the `releases` branch under the new release id
 
 Each step is described in detail below.
 

scripts/postversion.sh

@@ -12,18 +12,30 @@ node ./scripts/set-release-id-in-config-yml.cjs
 echo 'update changelog'
 ./scripts/update-changelog-page.sh
 
+echo 'commit changelog updates'
+git add docs/changelog.md
+git add docs/_config.yml
+git commit -n -m "Update docs/changelog.md and set new release id in docs/_config.yml"
+
 echo 'build new package'
 node ./build.cjs
 
-echo 'copying latest sinon to webpage assets'
-cp pkg/sinon.js ./docs/assets/js/
+echo 'publish to npm'
+git push --follow-tags && npm publish
+
+# Now update the releases branch and archive the new release
+git checkout releases
+git merge master
 
-echo 'copy new version'
+./scripts/copy-documentation-for-new-release.sh $PACKAGE_VERSION
+
+echo 'copying new version to webpage assets'
+cp "./pkg/sinon.js" "./docs/assets/js/"
+
+echo 'copy new version to release archive'
 cp "./pkg/sinon.js" "./docs/releases/sinon-$PACKAGE_VERSION.js"
 
 git add "docs/releases/sinon-$PACKAGE_VERSION.js"
-git add docs/changelog.md
-git add docs/_config.yml
-git commit -n -m "Update docs/changelog.md and set new release id in docs/_config.yml"
+git commit -n -m "Add version $PACKAGE_VERSION to releases"
 
-git push --follow-tags && npm publish
+git push && git checkout master