Make "Check License" workflow path filter handle either YAML extension

There are two file extensions in common use for YAML files: `.yaml` and `.yml`. Although this project uses `.yml`
exclusively for YAML files, this is a standardized workflow which might be applied to projects that have established the
use of the other extension. It will be most flexible if it supports both.

Author: per1234

.github/workflows/check-license.yml

@@ -9,7 +9,7 @@ env:
 on:
   push:
     paths:
-      - ".github/workflows/check-license.yml"
+      - ".github/workflows/check-license.ya?ml"
       # See: https://github.com/licensee/licensee/blob/master/docs/what-we-look-at.md#detecting-the-license-file
       - "[cC][oO][pP][yY][iI][nN][gG]*"
       - "[cC][oO][pP][yY][rR][iI][gG][hH][tH]*"
@@ -18,7 +18,7 @@ on:
       - "[pP][aA][tT][eE][nN][tT][sS]*"
   pull_request:
     paths:
-      - ".github/workflows/check-license.yml"
+      - ".github/workflows/check-license.ya?ml"
       - "[cC][oO][pP][yY][iI][nN][gG]*"
       - "[cC][oO][pP][yY][rR][iI][gG][hH][tH]*"
       - "[lL][iI][cC][eE][nN][cCsS][eE]*"