[SPARK-28578][INFRA] Improve Github pull request template

.github/PULL_REQUEST_TEMPLATE

@@ -1,10 +1,39 @@
-## What changes were proposed in this pull request?
+<!--
+Thanks for sending a pull request!  Here are some tips for you:
+  1. If this is your first time, please read our contributor guidelines: https://spark.apache.org/contributing.html
+  2. Ensure you have added or run the appropriate tests for your PR: https://spark.apache.org/developer-tools.html
+  3. If the PR is unfinished, add '[WIP]' in your PR title, e.g., '[WIP][SPARK-XXXX] Your PR title ...'.
+  4. Update your PR description whenever it is needed.
+  5. Provide a concise example to reproduce the issue if possible for a faster review.
+-->
 
-(Please fill in changes proposed in this fix)
+### What changes were proposed in this pull request?
+<!--
+Please clarify what changes you are proposing. The purpose of this section is to outline the changes and how this PR fixes the issue. 
+Therefore, if possible, please consider write some useful notes for better and faster reviews in your PR. See the examples below.
+  1. If you refactor some codes with changing classes, showing the class hierarchy will help reviewers.
+  2. If you fix some SQL features, you can provide some references of other DBMSes.
+  3. If there is a design documentation, please leave the link.
+  4. If there is a discussion in the mailing list, please leave the link.
+-->
 
-## How was this patch tested?
 
-(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
-(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)
+### Why are the changes needed?
+<!--
+Please clarify why the changes are needed. For instance,
+  1. If you propose a new API, clarify the usecase for a new API.
+  2. If you fixes a bug, you can calrify why it is a bug.
+-->
 
-Please review https://spark.apache.org/contributing.html before opening a pull request.
+### Does this PR introduce any user-facing change?
+<!--
+If yes, please clarify the previous behavior and the change this PR proposes - provide the console output, description and/or an example to show the behaviour difference if possible.
+If no, write 'No'.
+-->
+
+
+### How was this patch tested?
+<!--
+If some tests were added, say they were added here. Please make sure to add some test cases that check the changes thoroughly including negative and positive cases if possible.
+If it was tested in a way different from regular unit tests, please clarify how you tested step by step, ideally copy and paste-able, so that other reviewers can test and check through, and descendants can verify in the future.
+-->