chore: add issue template to propose new rules (#3925)

.github/ISSUE_TEMPLATE/eslint-plugin-typescript.yml

@@ -0,0 +1,41 @@
+name: Rule proposal
+description: "Propose a new rule for the '@typescript-eslint/eslint-plugin' package"
+title: "Rule proposal: "
+labels:
+  - "enhancement: new base rule extension"
+  - "package: eslint-plugin"
+  - triage
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Before opening a new issue:
+        - Look for existing [open or closed rule proposals](https://github.com/typescript-eslint/typescript-eslint/issues?q=label%3A%22enhancement%3A+new+base+rule+extension%22)
+        - Look for [existing rules](https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin)
+        - Ensure that the rule you want to propose is related to types. If not, consider looking into [eslint-plugin-unicorn](https://github.com/sindresorhus/eslint-plugin-unicorn)
+  - type: textarea
+    validations:
+      required: true
+    attributes:
+      label: Description
+      description: Explain here why this rule would be beneficial
+  - type: textarea
+    validations:
+      required: true
+    attributes:
+      label: Fail
+      description: Specify an example of code that should be detected
+      value: |
+        ```ts
+        var replace = 'me';
+        ```
+  - type: textarea
+    validations:
+      required: true
+    attributes:
+      label: Pass
+      description: Specify an example of code that would be accepted in its place
+      value: |
+        ```ts
+        const replace = 'me';
+        ```