Bump gradle-core from 5.6 to 6.0 in /jcp

Bumps gradle-core from 5.6 to 6.0.

---
updated-dependencies:
- dependency-name: org.gradle:gradle-core
  dependency-type: direct:production
...

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

Author: dependabot[bot]

jcp/pom.xml

@@ -22,7 +22,7 @@
   </repositories>
 
   <properties>
-    <gradle.api.version>5.6</gradle.api.version>
+    <gradle.api.version>6.0</gradle.api.version>
   </properties>
 
   <profiles>