chore: Update automatic labels in issue templates

Issue templates can set labels automatically on new issues.  We
already did this for questions, but not for bugs or features.

Now the label name for questions has changed, and needed to be
updated.  Also, for our new triage process, it is helpful to set bug
and enhancement labels automatically.

Change-Id: I28f79f0b5984709b117965c692e1e3aa774abb31

.github/ISSUE_TEMPLATE/bug_report.md

@@ -2,7 +2,7 @@
 name: Bug report
 about: Report a bug to help us improve
 title: ''
-labels: ''
+labels: 'type: bug'
 assignees: ''
 
 ---

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an idea for this project
 title: ''
-labels: ''
+labels: 'type: enhancement'
 assignees: ''
 
 ---

.github/ISSUE_TEMPLATE/question.md

@@ -3,7 +3,7 @@ name: Question
 about: An open-ended question or discussion about Shaka Player, but not a bug report
   or feature request
 title: ''
-labels: question
+labels: 'type: question'
 assignees: ''
 
 ---