Update issue_template.md

Make the template sections more distinctive for readability.

.github/issue_template.md

@@ -1,14 +1,12 @@
-Storage Explorer Version:
+**Storage Explorer Version:**
 
-OS Version:
+**OS Version:**
 
-Steps to Reproduce:
+**Steps to Reproduce:**
 
 1.
 2.
 
-Expected Experience:
-
-Actual Experience:
-
+**Expected Experience:**
 
+**Actual Experience:**