Bump snakeyaml from 1.26 to 1.28

Bumps [snakeyaml](https://bitbucket.org/asomov/snakeyaml) from 1.26 to 1.28.
- [Commits](https://bitbucket.org/asomov/snakeyaml/branches/compare/snakeyaml-1.28..snakeyaml-1.26)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

modello-plugins/modello-plugin-snakeyaml/pom.xml

@@ -24,7 +24,7 @@
     <dependency>
       <groupId>org.yaml</groupId>
       <artifactId>snakeyaml</artifactId>
-      <version>1.26</version>
+      <version>1.28</version>
     </dependency>
   </dependencies>