Update CONTRIBUTING.md (#237)

Update Contributing article

Author: JaneEugenia

CONTRIBUTING.md

@@ -1,23 +1,35 @@
 # How to contribute to UTBot Java
 
-## Want a new feature or change existing one?
-* Create an issue with proposal and describe your idea 
-* Wait for our feedback, it will be decided who is preparing the pull request: we may need your help or fix on our side
+To begin with, we are very thankful for your time and willingness to read this and contribute! 
 
-## Found a defect?
-Ensure this defect wasn't already reported in our [Issues](https://github.com/UnitTestBot/UTBotCpp/issues)
+The following guideline should help you with suggesting changes to our project, so feel free to use it for your contribution. 😃 
 
-If not - create a new one containing:
- * Environment *(describe your full setup)*
- * Pre-Conditions *(some special prerequisites)*
- * Steps to reproduce *(to be on the same page)*
- * Actual and expected result *(what went wrong?)*
 
-If you already have a PR with solution - link it with the created issue. 
+## I\`ve found a bug! How to report?
+
+First of all, please check our [Issues](https://github.com/UnitTestBot/UTBotJava/issues) — this bug may have already been reported, and you just don\`t need to spend your time on a new one.
+
+If you haven\`t found the relevant issue,  don\`t hesitate to [create a new one](https://github.com/UnitTestBot/UTBotJava/issues/new?assignees=&labels=&template=bug_report.md&title=), including as much detail as possible — the pre-made template will assist you in it.
+
+In case you already have a PR with a solution, please remain so amazing and link it with the created issue.
+
+
+## I have an improvement suggestion! 
+Want a new feature or to change the existing one? We are very welcome your fresh ideas. 😃
+
+Please [create an issue](https://github.com/UnitTestBot/UTBotJava/issues/new?assignees=&labels=&template=feature_request.md&title=) with your proposal and describe your idea with full information about it. By adding some examples you also bring much happiness to our souls!
+
+Give us some time to review your proposal and provide you with our feedback. It will be decided who is preparing the pull request: we may need your help or we will take care of it all. 🙂
+
+
+## Coding conventions
+Our team adheres to the defined requirements to coding style to optimize for readability. You can take a look on this [Coding style guide](https://github.com/saveourtool/diktat/blob/master/info/guide/diktat-coding-convention.md) to better understand what we expect to see in your code. 
+
 
 ## How to setup development environment?
 
-Please refer [Developer guide](DEVNOTE.md) to setup developer environment, build and run UTBot.
+Please refer [Developer guide](https://github.com/UnitTestBot/UTBotJava/blob/main/DEVNOTE.md) to setup developer environment, build and run UTBot.
+
 
 ## How to test you PR?