missing dependency check: assertj-core

[Pankraz76]

• [POC] Migrate JUnit asserts to AssertJ - impl apache/maven#2307
• [POC] Migrate JUnit asserts to AssertJ - impl apache/maven#2307 (comment)

bug

missing dependency check: assertj-core

      <dependency>
          <groupId>org.assertj</groupId>
          <artifactId>assertj-core</artifactId>
          <scope>test</scope>
      </dependency>

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[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.14.0:testCompile (default-testCompile) on project maven-api-plugin: Compilation failure: Compilation failure: 
[ERROR] /Users/vincent.potucek/IdeaProjects/maven/api/maven-api-plugin/src/test/java/org/apache/maven/api/plugin/descriptor/another/ExtendedPluginDescriptorTest.java:[24,35] package org.assertj.core.api does not exist
[ERROR] /Users/vincent.potucek/IdeaProjects/maven/api/maven-api-plugin/src/test/java/org/apache/maven/api/plugin/descriptor/another/ExtendedPluginDescriptorTest.java:[24,1] static import only from classes and interfaces
[ERROR] /Users/vincent.potucek/IdeaProjects/maven/api/maven-api-plugin/src/test/java/org/apache/maven/api/plugin/descriptor/another/ExtendedPluginDescriptorTest.java:[74,9] cannot find symbol
[ERROR]   symbol:   method assertThat(java.lang.String)
[ERROR]   location: class org.apache.maven.api.plugin.descriptor.another.ExtendedPluginDescriptorTest
[ERROR] /Users/vincent.potucek/IdeaProjects/maven/api/maven-api-plugin/src/test/java/org/apache/maven/api/plugin/descriptor/another/ExtendedPluginDescriptorTest.java:[75,9] cannot find symbol
[ERROR]   symbol:   method assertThat(java.lang.String)
[ERROR]   location: class org.apache.maven.api.plugin.descriptor.another.ExtendedPluginDescriptorTest
[ERROR] -> [Help 1]