Improve release workflow (#2719)

* add scripts to help with automating releases

* add prepare-release and release workflows

* bump actions from v2 to v3

* use `github.ref_name` for getting the tag name

* ensure we use `**` for matching tags with slashes in them

scripts/package-path.js

@@ -0,0 +1,15 @@
+// Given a version, figure out what the release notes are so that we can use this to pre-fill the
+// relase notes on a GitHub release for the current version.
+
+let path = require('path')
+let { execSync } = require('child_process')
+
+let tag = process.argv[2] || execSync(`git describe --tags --abbrev=0`).toString().trim()
+let pkgPath = path.resolve(
+  __dirname,
+  '..',
+  'packages',
+  tag.slice(0, tag.indexOf('@', 1)).replace('/', '-')
+)
+
+console.log('./' + path.relative(process.cwd(), pkgPath))

scripts/release-channel.js

@@ -0,0 +1,25 @@
+// Given a version, figure out what the release channel is so that we can publish to the correct
+// channel on npm.
+//
+// E.g.:
+//
+//   1.2.3                  -> latest (default)
+//   0.0.0-insiders.ffaa88  -> insiders
+//   4.1.0-alpha.4          -> alpha
+
+let tag = process.argv[2] || execSync(`git describe --tags --abbrev=0`).toString().trim()
+let pkgPath = path.resolve(
+  __dirname,
+  '..',
+  'packages',
+  tag.slice(0, tag.indexOf('@', 1)).replace('/', '-')
+)
+
+let version = require(path.resolve(pkgPath, 'package.json')).version
+
+let match = /\d+\.\d+\.\d+-(.*)\.\d+/g.exec(version)
+if (match) {
+  console.log(match[1])
+} else {
+  console.log('latest')
+}

scripts/release-notes.js

@@ -0,0 +1,29 @@
+// Given a version, figure out what the release notes are so that we can use this to pre-fill the
+// relase notes on a GitHub release for the current version.
+
+let path = require('path')
+let fs = require('fs')
+let { execSync } = require('child_process')
+
+let tag = process.argv[2] || execSync(`git describe --tags --abbrev=0`).toString().trim()
+let pkgPath = path.resolve(
+  __dirname,
+  '..',
+  'packages',
+  tag.slice(0, tag.indexOf('@', 1)).replace('/', '-')
+)
+
+let version = require(path.resolve(pkgPath, 'package.json')).version
+
+let changelog = fs.readFileSync(path.resolve(pkgPath, 'CHANGELOG.md'), 'utf8')
+let match = new RegExp(
+  `## \\[${version}\\] - (.*)\\n\\n([\\s\\S]*?)\\n(?:(?:##\\s)|(?:\\[))`,
+  'g'
+).exec(changelog)
+
+if (match) {
+  let [, , notes] = match
+  console.log(notes.trim())
+} else {
+  console.log(`Placeholder release notes for version: v${version}`)
+}