build: #5 pre-commit error when not php changed

Author: hms5232

src/stubs/git-pre-commit

@@ -1,3 +1,7 @@
 #!/bin/sh
 
-git diff --diff-filter=d --name-only HEAD | grep ".php$" | xargs ./vendor/bin/phpcs --standard=phpcs.xml
+files=$(git diff --diff-filter=d --name-only HEAD | grep ".php$")
+
+if [ -n "$files" ] ; then
+	./vendor/bin/phpcs --standard=phpcs.xml $files
+fi