docs: add feature requests and bug reports

.github/ISSUE_TEMPLATE/bug.yml

@@ -0,0 +1,35 @@
+name: Bug report for an existing lint rule, quick fix or assists.
+description: Report bug details you found and describe clearly as possible.
+title: '[Bug]: Title of the bug'
+labels: ['bug']
+assignees: ['@ronnnnn']
+body:
+  - type: dropdown
+    attributes:
+      label: Which feature types the bug belongs to?
+      description: Please select one or more types from belows.
+      multiple: true
+      options:
+        - Lint Rule
+        - Quick fix
+        - Assist
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Bug details
+      description: Please tell me bug details you found.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Environment
+      description: Which version of nilts, flutter and dart you use.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Additional context
+      description: Please describe additional context if you have.
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/feat.yml

@@ -0,0 +1,29 @@
+name: Feature request to add a new lint rule, quick fix or assists.
+description: Propose adding a new lint rule, quick fix or assists.
+title: '[Feat]: Title of the proposal'
+labels: ['feat']
+assignees: ['@ronnnnn']
+body:
+  - type: dropdown
+    attributes:
+      label: Which feature type would you like to add?
+      description: Please select one or more types from belows.
+      multiple: true
+      options:
+        - Lint Rule
+        - Quick fix
+        - Assist
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Describe the feature you'd like to add
+      description: Please tell me details you want.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Additional context
+      description: Please describe additional context if you have.
+    validations:
+      required: false

packages/nilts/README.md

@@ -109,6 +109,14 @@ See also: [flutter/flutter#114459](https://github.com/flutter/flutter/pull/11445
 
 Upcoming...
 
+## Feature requests
+
+If you have any feature requests, please create [an issue from this template](https://github.com/ronnnnn/nilts/issues/new?&labels=feat&template=feat.yml).
+
+## Bug reports
+
+If you find any bugs, please create [an issue from this template](https://github.com/ronnnnn/nilts/issues/new?&labels=bug&template=bug.yml).
+
 ## Contributing
 
 TBD