Add puppetlabs-apache to dependencies

Because we include some classes from puppetlabs-apache direcly, we
should include it in a list of dependencies.

Change-Id: I94ec49d646afdae537a0ab333dd27c40395ad270

metadata.json

@@ -1,6 +1,10 @@
 {
     "author": "OpenStack Contributors",
     "dependencies": [
+        {
+            "name": "puppetlabs/apache",
+            "version_requirement": ">=5.0.0"
+        },
         {
             "name": "puppetlabs/inifile",
             "version_requirement": ">=2.0.0 <3.0.0"