增加对httpclient、okhttpclient、rabbittemplate的依赖判断

brave-spring-boot-starter/pom.xml

@@ -46,17 +46,20 @@
         <dependency>
             <groupId>org.apache.httpcomponents</groupId>
             <artifactId>httpclient</artifactId>
+            <optional>true</optional>
         </dependency>
 
         <dependency>
             <groupId>com.squareup.okhttp3</groupId>
             <artifactId>okhttp</artifactId>
             <version>3.10.0</version>
+            <optional>true</optional>
         </dependency>
 
         <dependency>
             <groupId>org.springframework.amqp</groupId>
             <artifactId>spring-rabbit</artifactId>
+            <optional>true</optional>
         </dependency>
 
         <dependency>