fix pinning of thyeleaf in server-openapi

Author: sb-benohe

apps/bfd-server-openapi/pom.xml

@@ -59,7 +59,7 @@
         <dependency>
             <groupId>org.thymeleaf</groupId>
             <artifactId>thymeleaf</artifactId>
-            <version>3.1.4.RELEASE</version>
+            <version>${thymeleaf.version}</version>
         </dependency>
         <dependency>
             <groupId>com.vladsch.flexmark</groupId>