Fix SUBNET capitalization in issue template (#3345)

Author: kaankabalak

.github/ISSUE_TEMPLATE/bug_report.md

@@ -8,7 +8,7 @@ assignees: ''
 ---
 
 ## NOTE
-If this case is urgent, please subscribe to [Subnet](https://min.io/pricing) so that our 24/7 support team may help you faster.
+If this case is urgent, please subscribe to [SUBNET](https://min.io/pricing) so that our 24/7 support team may help you faster.
 
 <!--- Provide a general summary of the issue in the title above -->