Doc: PR Template and update issue template

.github/pull_request_template.md

@@ -0,0 +1,31 @@
+---
+name: Pull Request Template
+about: Pull Request
+title: ''
+assignees: ''
+
+---
+
+**Describe the PR**
+A clear and concise description of what the PR is.
+
+**Related Issue**
+
+**Screenshots**
+If applicable, add screenshots to help explain your commit.
+
+**Environment (please complete the following information):**
+Check like `- [x]`.
+
+ - PR Type
+  - `Add:` Add feature or enhanced.
+  - `Fix:` Bug fix or change default values.
+  - `Clean:` Refactoring.
+  - `Doc:` Update docs.
+ - Distribution
+   - [ ] [Original Lepton](https://github.com/black7375/Firefox-UI-Fix)
+   - [ ] [Lepton's photon style](https://github.com/black7375/Firefox-UI-Fix/tree/photon-style)
+   - [ ] [Lepton's proton style](https://github.com/black7375/Firefox-UI-Fix/tree/proton-style)
+
+**Additional context**
+Add any other context about the commit here.