Add "needs triage" label to issue templates (#8643)

This label would make it easier for issue triagers to know what they
haven't triaged yet.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 name: Bug report
 description: Create a bug report to help us improve
-labels: [bug]
+labels: [bug, needs triage]
 body:
   - type: markdown
     attributes:

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,6 +1,6 @@
 name: Feature request
 description: Suggest an idea for this project
-labels: [enhancement]
+labels: [enhancement, needs triage]
 body:
   - type: markdown
     attributes:

.github/ISSUE_TEMPLATE/question.yml

@@ -1,6 +1,6 @@
 name: Question
 description: Ask about anything NewPipe-related
-labels: [question]
+labels: [question, needs triage]
 body:
   - type: markdown
     attributes: