Update text and links for ISSUE_TEMPLATE (#43)

Author: kenneth-lau

.github/ISSUE_TEMPLATE.md

@@ -1,7 +1,7 @@
 ## Do this before creating an issue
 
-- Check the [FAQ](https://github.com/line/line-bot-faq) for LINE bots
-- Make sure your issue is **related to** the LINE Bot SDK. For general questions or issues about LINE bots, create an issue on the [FAQ](https://github.com/line/line-bot-faq) repository. Note that we don't provide technical support.
+- Check our [developer documentation](https://developers.line.me/en/docs/) and [FAQ](https://developers.line.me/en/faq/messaging-api/) page for more information on LINE bots and the Messaging API
+- Make sure your issue is **related to** the LINE Bot SDK. For general questions or issues about LINE bots, create an issue on the [LINE Platform feedback](https://github.com/line/line-platform-feedback) repository. Note that we don't provide technical support.
 
 ## When creating an issue