chore: improve PR template (#737)

<!---
☝️ PR title should follow conventional commits
(https://conventionalcommits.org)
-->

### 🔗 Linked issue

<!-- If it resolves an open issue, please link the issue here. For
example "Resolves #123" -->

### ❓ Type of change

<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply. -->

- [ ] 📖 Documentation (updates to the documentation or readme)
- [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
- [ ] 👌 Enhancement (improving an existing functionality)
- [ ] ✨ New feature (a non-breaking change that adds functionality)
- [ ] 🧹 Chore (updates to the build process or auxiliary tools and
libraries)
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to change)

### 📚 Description

Remove the type of change block since it is unnecessary.

<!-- Describe your changes in detail -->
<!-- Why is this change required? What problem does it solve? -->

.github/pull_request_template.md

@@ -1,22 +1,18 @@
-<!---
-☝️ PR title should follow conventional commits (https://conventionalcommits.org)
+<!--
+☝️ PR title should follow conventional commits (https://conventionalcommits.org).
+In particular, the title should start with one of the following types:
+
+- docs: 📖 Documentation (updates to the documentation or readme)
+- fix: 🐞 Bug fix (a non-breaking change that fixes an issue)
+- feat: ✨ New feature/enhancement (a non-breaking change that adds functionality or improves existing one)
+- feat!/fix!: ⚠️ Breaking change (fix or feature that would cause existing functionality to change)
+- chore: 🧹 Chore (updates to the build process or auxiliary tools and libraries)
 -->
 
 ### 🔗 Linked issue
 
 <!-- If it resolves an open issue, please link the issue here. For example "Resolves #123" -->
 
-### ❓ Type of change
-
-<!-- What types of changes does your code introduce? Put an `x` in all the boxes that apply. -->
-
-- [ ] 📖 Documentation (updates to the documentation or readme)
-- [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
-- [ ] 👌 Enhancement (improving an existing functionality)
-- [ ] ✨ New feature (a non-breaking change that adds functionality)
-- [ ] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
-- [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)
-
 ### 📚 Description
 
 <!-- Describe your changes in detail -->