CI: Fix eslint usage

commit d7c7951 changed the installation
of eslint to use package.json instead of installing it globally. So
adapt the usage of eslint to that.

.github/workflows/run-ci.yml

@@ -18,7 +18,7 @@ jobs:
         run: >
           git diff --name-only --diff-filter=ACMTUXB origin/${{ github.base_ref }} HEAD |
           grep -E "\.js$" |
-          xargs -r eslint
+          xargs -r npx eslint
       - name: Run ShellCheck (*.sh)
         if: success() || failure()
         run: >