Bump assertj-core from 3.13.2 to 3.14.0 in /core (#2005)

Bumps [assertj-core](https://github.com/joel-costigliola/assertj-core) from 3.13.2 to 3.14.0.
- [Release notes](https://github.com/joel-costigliola/assertj-core/releases)
- [Commits](assertj/assertj@assertj-core-3.13.2...assertj-core-3.14.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: null <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

core/build.gradle

@@ -115,12 +115,12 @@ dependencies {
     // Synthetic JAR used for MountableFileTest and DirectoryTarResourceTest
     testCompile files('testlib/repo/fakejar/fakejar/0/fakejar-0.jar')
 
-    testCompile 'org.assertj:assertj-core:3.13.2'
+    testCompile 'org.assertj:assertj-core:3.14.0'
     testCompile project(':test-support')
 
     jarFileTestCompileOnly "org.projectlombok:lombok:${lombok.version}"
     jarFileTestAnnotationProcessor "org.projectlombok:lombok:${lombok.version}"
     jarFileTestCompile 'junit:junit:4.12'
-    jarFileTestCompile 'org.assertj:assertj-core:3.12.2'
+    jarFileTestCompile 'org.assertj:assertj-core:3.14.0'
     jarFileTestCompile 'org.ow2.asm:asm-debug-all:5.2'
 }