Update label names in issue templates

This repositories label names have been customized. The label names defined in the templates will automatically be added
to issues created using that template, so the template labels must match with the repository's labeling convention.

Author: per1234

Diff for: .github/ISSUE_TEMPLATE/bug_report.md

@@ -2,7 +2,7 @@
 name: Bug report
 about: Create a report to help us improve
 title: ''
-labels: bug
+labels: 'type: bug'
 assignees: ''
 
 ---

Diff for: .github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an idea for this project
 title: ''
-labels: enhancement
+labels: 'type: enhancement'
 assignees: ''
 
 ---