Chore: Add new issue templates (#635)

* Chore: Add new issue templates

https://blog.github.com/2018-05-02-issue-template-improvements/

* Update bug_report.md

* Update rule-proposal.md

Author: armano2

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,34 @@
+---
+name: Bug report
+about: Create a report to help us improve
+
+---
+
+<!--
+  Before posting the issue, please confirm that the problem you're getting
+  is not related with your code editor configuration.
+  To make sure it's not, run: yarn eslint src/your-file.vue
+-->
+
+**Tell us about your environment**	
+* **ESLint version:**	
+* **eslint-plugin-vue version:**	
+* **Node version:**	
+
+**Please show your full configuration:**
+<!-- Paste content of your .eslintrc file -->
+```json
+
+```
+
+**What did you do?**	
+<!-- Please include the actual source code causing the issue. -->
+```vue
+
+```
+
+**What did you expect to happen?**
+
+
+**What actually happened?**
+<!-- Please include the actual, raw output from ESLint. -->

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,29 @@
+---
+name: Rule Proposal
+about: Suggest an idea for a new rule
+
+---
+
+<!--
+  Before proposing new rule, please make sure it hasn't been posted already.
+  You can see all open propositions here:
+  https://github.com/vuejs/eslint-plugin-vue/issues?q=is%3Aopen+is%3Aissue+label%3A%22new+rule+proposition%22
+-->
+
+**Please describe what the rule should do:**
+<!-- A clear and concise description of what the rule should do. -->
+
+**What category should the rule belong to?**
+<!-- (place an "X" next to just one item) -->
+- [ ] Enforces code style
+- [ ] Warns about a potential error
+- [ ] Suggests an alternate way of doing something
+- [ ] Other (please specify:)
+
+**Provide 2-3 code examples that this rule should warn about:**
+```vue
+
+```
+
+**Additional context**
+<!-- Add any other context or screenshots about the feature request here. -->