chore: update gitignore list (#9437)

Updated the gitignore list with the command : `go run scripts/generate-gitignores.go`

options/gitignore/Splunk

@@ -0,0 +1,8 @@
+# gitignore template for Splunk apps
+# documentation: http://docs.splunk.com/Documentation/Splunk/6.2.3/admin/Defaultmetaconf
+
+# Splunk local meta file
+local.meta
+
+# Splunk local folder
+local