chore: remove automatic assignees from issue templates

Removed automatic assignees from bug report, feature request, and thumbnail request templates. This change aims to distribute issue assignment more dynamically among team members, ensuring a more balanced workload and allowing for flexibility in issue triage.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -3,7 +3,6 @@ name: Bug report
 about: Create a report to help us improve
 title: ''
 labels: new issue
-assignees: flocke
 
 ---
 

.github/ISSUE_TEMPLATE/feature-request.md

@@ -3,7 +3,6 @@ name: Feature request
 about: Suggest an idea for this project
 title: ''
 labels: enhancement
-assignees: flocke
 
 ---
 

.github/ISSUE_TEMPLATE/thumbnail-request.md

@@ -3,7 +3,6 @@ name: Thumbnail request
 about: Request a new thumbnail
 title: "[Thumbnail]"
 labels: enhancement, thumbnail
-assignees: flocke, RichyHBM, ziegenberg
 
 ---