Update snakeyaml to 1.19 to fix bug with duplicate keys affecting some users.

https://bitbucket.org/asomov/snakeyaml/issues/386/duplicate-keys-cause-issues

By: md_5 <git@md-5.net>

paper-api/pom.xml

@@ -73,7 +73,7 @@
         <dependency>
             <groupId>org.yaml</groupId>
             <artifactId>snakeyaml</artifactId>
-            <version>1.18</version>
+            <version>1.19</version>
             <scope>compile</scope>
         </dependency>
         <!-- testing -->