Bump org.hibernate:hibernate-osgi from 5.6.7.Final to 5.6.15.Final (#2001)

Bumps [org.hibernate:hibernate-osgi](https://github.com/hibernate/hibernate-orm) from 5.6.7.Final to 5.6.15.Final.
- [Release notes](https://github.com/hibernate/hibernate-orm/releases)
- [Changelog](https://github.com/hibernate/hibernate-orm/blob/5.6.15/changelog.txt)
- [Commits](https://github.com/hibernate/hibernate-orm/compare/5.6.7...5.6.15)

---
updated-dependencies:
- dependency-name: org.hibernate:hibernate-osgi
  dependency-version: 5.6.15.Final
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/pom.xml b/pom.xml
index 49ffb5a..c75399a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -277,7 +277,7 @@
         <guava.version>20.0</guava.version>
         <narayana.version>5.13.1.Final</narayana.version>
         <hibernate.ejb.version>3.4.0.GA</hibernate.ejb.version>
-        <hibernate.version>5.6.7.Final</hibernate.version>
+        <hibernate.version>5.6.15.Final</hibernate.version>
         <hibernate.validator.version>7.0.2.Final</hibernate.validator.version>
         <httpclient.version>4.5.14</httpclient.version>
         <jansi.version>2.4.2</jansi.version>