docs: add version info in playground.html

bin/build-changelog.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+cd docs
+cp ../CHANGELOG.md source/tutorials/changelog.md
+sed -i \
+  -e 's/{%/{% raw %}{%{% endraw %}/g' \
+  -e 's/{{/{% raw %}{{{% endraw %}/g' \
+  -e '1 s/"/\"/g' \
+  -e '1 s/</\&lt;/g' \
+  -e '1 s/>/\&gt;/g' \
+  source/tutorials/changelog.md
+cp source/tutorials/changelog.md source/zh-cn/tutorials/changelog.md
+
+sed -i '1i ---\ntitle: Changelog\nauto: true\n---\n' source/tutorials/changelog.md
+sed -i '1i ---\ntitle: 更新日志\nauto: true\n---\n' source/zh-cn/tutorials/changelog.md