[#184] Remove legacy CloudEvents support

The existing classes for supporting the creation, mapping and validation
of CloudEvents are not needed anymore because all uProtocol APIs use
UMessage and UAttributes as parameter types. Application developers
do not need to bother with CloudEvents anymore.

Also bumped version to 3.0.0-SNAPSHOT

Fixes #184

Author: sophokles73

README.adoc

@@ -53,10 +53,6 @@ To pull the Library from maven central, setting ${uprotocol.version} to the late
 | uProtocol unique identifier builders, validators, and serializers.
 | Basics
 
-| link:src/main/java/org/eclipse/uprotocol/cloudevent/README.adoc[`*cloudevent*`] 
-| A representation of uProtocol messages used in older versions of the specifications kept for backwards compatibility.
-| Legacy
-
 |===
 
 === Building from Source

pom.xml

@@ -17,7 +17,7 @@
     <artifactId>up-java</artifactId>
     <name>Java Library for uProtocol</name>
     <description>Language specific uProtocol library for building and using UUri, UUID, UAttributes, UTransport, and more</description>
-    <version>2.0.1-SNAPSHOT</version>
+    <version>3.0.0-SNAPSHOT</version>
     <packaging>jar</packaging>
     <url>https://github.com/eclipse-uprotocol/up-java/</url>    
 
@@ -76,37 +76,11 @@
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
-            <dependency>
-                <groupId>io.cloudevents</groupId>
-                <artifactId>cloudevents-bom</artifactId>
-                <version>4.0.1</version>
-                <type>pom</type>
-                <scope>import</scope>
-            </dependency>
         </dependencies>
     </dependencyManagement>
 
     <dependencies>
 
-        <!-- CloudEvents support https://cloudevents.github.io/sdk-java/
-        https://github.com/cloudevents/sdk-java-->
-        <dependency>
-            <groupId>io.cloudevents</groupId>
-            <artifactId>cloudevents-core</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>io.cloudevents</groupId>
-            <artifactId>cloudevents-api</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>io.cloudevents</groupId>
-            <artifactId>cloudevents-json-jackson</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>io.cloudevents</groupId>
-            <artifactId>cloudevents-protobuf</artifactId>
-        </dependency>
-
         <dependency>
             <groupId>com.google.protobuf</groupId>
             <artifactId>protobuf-java</artifactId>