Adds triage label to issue templates

Adds a triage label by default to the issue templates for project
maintainers to identify new issues that still need to be evaluated,
labeled, and addressed.

Change-Id: I9508cce273e7834ccff5eb77c0dd6a1e028dc299

.github/ISSUE_TEMPLATE/bug_report.md

@@ -2,7 +2,7 @@
 name: Bug report
 about: Report a bug or unexpected airshipctl behavior
 title: ''
-labels: bug
+labels: bug, triage
 assignees: ''
 
 ---

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an airshipctl feature
 title: ''
-labels: enhancement
+labels: enhancement, triage
 assignees: ''
 
 ---