Bump org.yaml:snakeyaml from 2.5 to 2.6

Bumps [org.yaml:snakeyaml](https://bitbucket.org/snakeyaml/snakeyaml) from 2.5 to 2.6.
- [Commits](https://bitbucket.org/snakeyaml/snakeyaml/branches/compare/snakeyaml-2.6..snakeyaml-2.5)

---
updated-dependencies:
- dependency-name: org.yaml:snakeyaml
  dependency-version: '2.6'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

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

@@ -24,7 +24,7 @@
     <dependency>
       <groupId>org.yaml</groupId>
       <artifactId>snakeyaml</artifactId>
-      <version>2.5</version>
+      <version>2.6</version>
     </dependency>
     <!--      needed for modello compiler test(inside)-->
     <dependency>