Fix labels in issue templates

.github/ISSUE_TEMPLATE/feature_request.md

 ---
 name: Feature request
 about: Suggest a feature for Oh My Zsh
-labels: 'feature'
+labels: 'Feature'
 
 ---
 

.github/ISSUE_TEMPLATE/support.md

 ---
 name: Support
 about: Request support for any problem you're having with Oh My Zsh
-labels: 'support'
+labels: 'Support'
 
 ---