Convert the Bug report template

Author: dshevtsov

.github/ISSUE_TEMPLATE/BUG.md

@@ -0,0 +1,50 @@
+name: Bug report
+description: Technical issue with https://devdocs.magento.com/
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thank you for taking the time to report this issue!
+        GitHub Issues in this repo should relate to this project's codebase.
+        Before submitting this issue, please make sure you are complying with our [Code of Conduct](https://github.com/magento/devdocs/blob/master/.github/CODE_OF_CONDUCT.md):
+        Issues that do not comply with our Code of Conduct or do not contain enough information may be closed at the maintainers' discretion.
+  - type: checkboxes
+    attributes:
+      label: Is there an existing issue for this?
+      description: Please search to see if an issue already exists for the bug you encountered.
+      options:
+        - label: I have searched the existing issues
+          required: true
+  - type: textarea
+    attributes:
+      label: Current behavior
+      description: |
+        Tell us what happened. Include error messages and issues.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Expected behavior
+      description: |
+        Tell us what you expected to happen.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Steps to reproduce
+      description: |
+        Provide a set of clear steps to reproduce this bug.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Environment
+      description: |
+        Describe your environment.
+        Provide all the details that will help us to reproduce the bug.
+      value: |
+        - Browser:
+        - OS:
+    validations:
+      required: true