Bump okhttp from 3.12.1 to 3.14.2 in /core

Bumps [okhttp](https://github.com/square/okhttp) from 3.12.1 to 3.14.2.
- [Release notes](https://github.com/square/okhttp/releases)
- [Changelog](https://github.com/square/okhttp/blob/master/CHANGELOG.md)
- [Commits](square/okhttp@parent-3.12.1...parent-3.14.2)

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

core/build.gradle

@@ -92,7 +92,7 @@ dependencies {
         exclude(group: 'org.apache.commons', module: 'commons-compress')
     }
 
-    shaded 'com.squareup.okhttp3:okhttp:3.12.1'
+    shaded 'com.squareup.okhttp3:okhttp:3.14.2'
 
     shaded 'org.glassfish.main.external:trilead-ssh2-repackaged:4.1.2'