(CONT-200) Fix require relative paths

Prior to this commit using stdlib/to_toml function in a
separate environment outside of production will result
in the following error if the latest version doesn't
also live in production:

```
Error: Could not retrieve catalog from remote server:
Error 500 on SERVER: Internal Server Error:
org.jruby.exceptions.LoadError: (LoadError)
no such file to load -- puppet_x/stdlib
```

This commit fixes the issue by updating code to use the correct paths
for require_relative.

Author: chelnak

lib/puppet_x/stdlib.rb

@@ -1,4 +1,4 @@
-require 'puppet_x'
+require_relative '../puppet_x'
 
 # common PuppetX::Stdlib module definition
 module PuppetX::Stdlib; end

lib/puppet_x/stdlib/toml_dumper.rb

@@ -18,7 +18,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 
-require_relative '../stdlib'
+require_relative '../../puppet_x/stdlib'
 require 'date'
 
 module PuppetX::Stdlib