chore: allow nightlies from release branches (#14157)

* chore: allow nightlies from release branches

* keep current version from beta to nightly

* move version bump logic to bump-versi.py

script/get-last-major-for-master.js

@@ -0,0 +1,29 @@
+const { GitProcess } = require('dugite')
+const path = require('path')
+const semver = require('semver')
+const gitDir = path.resolve(__dirname, '..')
+
+async function determineNextMajorForMaster () {
+  let branchNames
+  let result = await GitProcess.exec(['branch', '-a', '--remote', '--list', 'origin/[0-9]-[0-9]-x'], gitDir)
+  if (result.exitCode === 0) {
+    branchNames = result.stdout.trim().split('\n')
+    const filtered = branchNames.map(b => b.replace('origin/', ''))
+    return getNextReleaseBranch(filtered)
+  } else {
+    throw new Error('Release branches could not be fetched.')
+  }
+}
+
+function getNextReleaseBranch (branches) {
+  const converted = branches.map(b => b.replace(/-/g, '.').replace('x', '0'))
+  const next = converted.reduce((v1, v2) => {
+    return semver.gt(v1, v2) ? v1 : v2
+  })
+  return parseInt(next.split('.')[0], 10)
+}
+
+determineNextMajorForMaster().then(console.info).catch((err) => {
+  console.error(err)
+  process.exit(1)
+})