Fix GitHub releases of vscode-mdx (#369)

The solution is based on
https://github.com/statelyai/xstate-tools/blob/8a5df5db0e96e097b51e58280ae6405f2a0f9f94/scripts/tag-extension.js

Author: remcohaszing

release.sh

@@ -3,6 +3,7 @@ npm pack --pack-destination "$PWD" --workspace @mdx-js/language-service
 npm pack --pack-destination "$PWD" --workspace @mdx-js/language-server
 npx --workspace vscode-mdx vsce package --out "$PWD"
 
+node scripts/tag-extension.mjs
 npx changeset publish
 npx ovsx publish --packagePath ./*.vsix
 npx vsce publish --packagePath ./*.vsix

scripts/tag-extension.mjs

@@ -0,0 +1,24 @@
+#!/usr/bin/env node
+import assert from 'node:assert/strict'
+import {spawnSync} from 'node:child_process'
+// eslint-disable-next-line import/order
+import {createRequire} from 'node:module'
+
+const require = createRequire(import.meta.url)
+const pkg = require('../packages/vscode-mdx/package.json')
+
+const tag = `${pkg.name}@${pkg.version}`
+
+const {status, stdout, error} = spawnSync('git', [
+  'ls-remote',
+  pkg.repository.url,
+  tag
+])
+
+assert.equal(status, 0, error)
+
+const exists = String(stdout).trim() !== ''
+
+if (!exists) {
+  console.log(`\nNew tag: ${tag}`)
+}