naming consistency

Author: NellowTCS

.github/workflows/single_file.yml .github/workflows/single-file.yml.github/workflows/single_file.yml renamed to .github/workflows/single-file.yml

@@ -38,4 +38,4 @@ jobs:
         with:
           name: HTMLPlayer-Standalone
           path: Build/dist/HTMLPlayer-v2.html
-          if-no-files-found: error
+          if-no-files-found: error