Refactor headers in bug report template

Updated section headers in bug report template to use consistent formatting.

Signed-off-by: Lee Calcote <lee.calcote@layer5.io>

Author: leecalcote

.github/ISSUE_TEMPLATE/bug_report.md

@@ -6,19 +6,19 @@ labels: 'kind/bug'
 assignees: ''
 ---
 
-#### Current Behavior
+### Current Behavior
 
 <!-- A brief description of the issue. -->
 
-#### Expected Behavior
+### Expected Behavior
 
 <!-- A brief description of what you expected to happen. -->
 
-#### Screenshots/Logs
+### Screenshots/Logs
 
 <!-- Add screenshots, if applicable, to help explain your problem. -->
 
-#### Environment
+### Environment
 
 <!-- Please mention the environment where you encountered the issue (e.g., browser, OS, etc.). -->