implement MavenTargetDependency equals comparison

In the TargetPlatformPreferencePage, upon the Apply button, some target
definition containing some MavenTargetLocation always is rewritten to
it's .target file, when MavenTargetDependency lacks an impl of equals(),
causing MavenTargetLocation.roots to never be equal.

org.eclipse.m2e.pde.target/src/org/eclipse/m2e/pde/target/MavenTargetDependency.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2021, 2023 Christoph Läubrich and others
+ * Copyright (c) 2021, 2023, 2024 Christoph Läubrich and others
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -76,4 +76,15 @@ public boolean matches(Dependency other) {
 				&& Objects.equals(other.getClassifier(), getClassifier());
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		return obj instanceof MavenTargetDependency other
+				&& Objects.equals(other.getGroupId(), getGroupId())
+				&& Objects.equals(other.getArtifactId(), getArtifactId())
+				&& Objects.equals(other.getVersion(), getVersion()) && Objects.equals(other.getType(), getType())
+				&& Objects.equals(other.getClassifier(), getClassifier());
+	}
 }