Correct issue label names per recent changes (#160)

Issue labels have been reworked recently, causing some files in
`.github` to reference non-existing issue labels. This PR updates the
names of labels in these files.

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -1,6 +1,6 @@
 name: Bug Report
 description: Create a report to help us improve
-labels: [ "bug" ]
+labels: [ "type: bug" ]
 body:
     - type: markdown
       attributes:

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -1,6 +1,6 @@
 name: Feature Request
 description: Create a request for a feature you would like
-labels: [ "type: enhancement" ]
+labels: [ "type: feature" ]
 body:
     - type: textarea
       id: background