[RNKC-066] - PR template emojis (#74)

## 📜 Description

Added emojis for PR template.

## 💡 Motivation and Context

To make it more readable I decided to add emojis for PR templates to
headers. In my opinion it looks better visually and it's easier to read
sections.

## 📢 Changelog

### Docs
- updated PR template;

## 🤔 How Has This Been Tested?

Tested in this PR 😅 

## 📝 Checklist

- [x] CI successfully passed

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,11 @@
-## Description
+## 📜 Description
 <!-- Describe your changes in detail -->
 
-## Motivation and Context
+## 💡 Motivation and Context
 <!-- Why is this change required? What problem does it solve? -->
 <!-- If it fixes an open issue, please link to the issue here. -->
 
-## Changelog
+## 📢 Changelog
 
 <!-- High level overview of important changes -->
 <!-- For example: fixed status bar manipulation; added new types declarations; -->
@@ -23,15 +23,15 @@
 - 
 - 
 
-## How Has This Been Tested?
+## 🤔 How Has This Been Tested?
 <!-- Please describe in detail how you tested your changes. -->
 <!-- Include details of your testing environment, and the tests you ran to -->
 <!-- see how your change affects other areas of the code, etc. -->
 
-## Screenshots (if appropriate):
+## 📸 Screenshots (if appropriate):
 <!-- Add screenshots/video if needed -->
 <!-- That would be highly appreciated if you can add how it looked before and after your changes -->
 
-## Checklist
+## 📝 Checklist
 
 - [ ] CI successfully passed