Improve issue templates

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

.github/ISSUE_TEMPLATE/bug_report.md

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 name: 🐛 Bug report
-about: Create a report to help us improve our platform
+about: Report a bug to help us improve Dex
 ---
 <!--
 Thank you for sending a bug report! Here some tips:

.github/ISSUE_TEMPLATE/feature_request.md

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 name: 🚀 Feature request
-about: Suggest an idea for this project
+about: Suggest an idea for Dex
 ---
 <!--
  Thank you for sending a feature request!