Use github read-only urls plugin_config.yml

Since those repos are usually cloned for read only purpose on production machines it should be sufficient this way.

plugin_config.yml

@@ -1,23 +1,23 @@
 ---
 plugins/chiliproject_activity_module:
-  repository: "git@github.com:finnlabs/chiliproject_activity_module.git"
+  repository: "git://github.com/finnlabs/chiliproject_activity_module.git"
   branch: master
 plugins/help_link:
-  repository: "git@github.com:finnlabs/help_link.git"
+  repository: "git://github.com/finnlabs/help_link.git"
   branch: master
 plugins/numbered_headings:
-  repository: "git@github.com:finnlabs/numbered_headings.git"
+  repository: "git://github.com/finnlabs/numbered_headings.git"
   branch: master
 plugins/redmine_checkout:
-  repository: "git@github.com:finnlabs/redmine_checkout.git"
+  repository: "git://github.com/finnlabs/redmine_checkout.git"
   branch: master
 plugins/customize_modules:
-  repository: "git@github.com:finnlabs/customize_modules.git"
+  repository: "git://github.com/finnlabs/customize_modules.git"
   branch: master
 plugins/redmine_favicon:
-  repository: "git@github.com:finnlabs/redmine_favicon.git"
+  repository: "git://github.com/finnlabs/redmine_favicon.git"
   branch: master
 plugins/memcached_passenger:
-  repository: "git@github.com:finnlabs/memcached_passenger.git"
+  repository: "git://github.com/finnlabs/memcached_passenger.git"
   branch: master