change the configurtion to work default with multicast address

[khanimteyaz]

What is the purpose of the change

Making changes in dubbo-demo-consumer.xml to use multicast as provider is configured to multicast. So that dubbo demo user can use the sample without any external configuration.

Brief changelog

Making changes in dubbo-demo-consumer.xml to use multicast as provider is configured to multicast. So that dubbo demo user can use the sample without any external configuration.

Verifying this change

Running locally dubbo-demo provider and consumer and seeing the request-response messages.

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[codecov-io]

Codecov Report

Merging #3092 into master will decrease coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3092      +/-   ##
============================================
- Coverage      63.5%   63.46%   -0.05%     
  Complexity       75       75              
============================================
  Files           653      653              
  Lines         28251    28251              
  Branches       4816     4816              
============================================
- Hits          17942    17930      -12     
- Misses         8040     8046       +6     
- Partials       2269     2275       +6

Impacted Files	Coverage Δ	Complexity Δ
.../remoting/transport/netty4/NettyClientHandler.java	75% <0%> (-11.12%)	0% <0%> (ø)
...onfig/spring/extension/SpringExtensionFactory.java	78.04% <0%> (-7.32%)	0% <0%> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	57.64% <0%> (-4.71%)	0% <0%> (ø)
...he/dubbo/remoting/transport/netty/NettyServer.java	67.85% <0%> (-3.58%)	0% <0%> (ø)
...c/main/java/org/apache/dubbo/rpc/RpcException.java	82.75% <0%> (-3.45%)	0% <0%> (ø)
...dubbo/remoting/exchange/support/DefaultFuture.java	73.15% <0%> (-2.02%)	0% <0%> (ø)
...he/dubbo/registry/multicast/MulticastRegistry.java	63.79% <0%> (-1.73%)	0% <0%> (ø)
...rpc/protocol/dubbo/telnet/InvokeTelnetHandler.java	72.5% <0%> (-1.67%)	0% <0%> (ø)
.../java/org/apache/dubbo/config/ReferenceConfig.java	57.95% <0%> (+0.37%)	0% <0%> (ø)	⬇️
...pache/dubbo/registry/support/AbstractRegistry.java	81.95% <0%> (+0.75%)	0% <0%> (ø)	⬇️
... and 1 more

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[ralf0131]

LGTM, thanks for the pull request!