feat: add publish-subscribe design pattern (#2898) (#3223)

* feat: add publisher-subscriber design pattern (#2898)

* fix: check styles on publisher-subscriber design pattern (#2898)

* fix: check styles on publisher-subscriber design pattern (#2898)

* fix: check styles on publisher-subscriber design pattern (#2898)

* fix: improve coverage on publisher-subscriber design pattern (#2898)

* fix: fix dependancy on publisher-subscriber design pattern (#2898)

* fix: fix documentation on publisher-subscriber design pattern (#2898)

* fix: apply spotless on publisher-subscriber design pattern (#2898)

* fix: changes after review on publisher-subscriber design pattern (#2898)

* fix: changes after review on publisher-subscriber design pattern (#2898)

* fix: fix sonar on publisher-subscriber design pattern (#2898)

* fix: fix sonar on publisher-subscriber design pattern (#2898)

---------

Co-authored-by: Sanura Hettiarachchi <sanura.hettiarachchi@tipico.com>

publish-subscribe/pom.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.iluwatar</groupId>
+        <artifactId>java-design-patterns</artifactId>
+        <version>1.26.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>publish-subscribe</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>