update version to 5.5.4-snapshot

[leizhiyuan]

Motivation:

Explain the context, and why you're making that change.
To make others understand what is the problem you're trying to solve.

Modification:

Describe the idea and modifications you've done.

Result:

Fixes #.

If there is no issue then describe the changes introduced by this PR.

[codecov]

Codecov Report

Merging #622 into 5.5 will increase coverage by 0.07%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                5.5     #622      +/-   ##
============================================
+ Coverage     71.08%   71.15%   +0.07%     
- Complexity     1142     1146       +4     
============================================
  Files           377      377              
  Lines         15786    15786              
  Branches       2556     2556              
============================================
+ Hits          11221    11233      +12     
+ Misses         3226     3215      -11     
+ Partials       1339     1338       -1

Impacted Files	Coverage Δ	Complexity Δ
.../main/java/com/alipay/sofa/rpc/common/Version.java	100% <ø> (ø)	0 <0> (ø)	⬇️
.../main/java/com/alipay/sofa/rpc/tracer/Tracers.java	41.02% <0%> (-2.57%)	0% <0%> (ø)
...alipay/sofa/rpc/registry/zk/ZookeeperRegistry.java	63.25% <0%> (+0.6%)	0% <0%> (ø)	⬇️
...va/com/alipay/sofa/rpc/server/rest/RestServer.java	74.13% <0%> (+0.86%)	0% <0%> (ø)	⬇️
.../sofa/rpc/bootstrap/DefaultClientProxyInvoker.java	91.93% <0%> (+1.61%)	0% <0%> (ø)	⬇️
...n/java/com/alipay/sofa/rpc/common/SofaConfigs.java	82.14% <0%> (+1.78%)	0% <0%> (ø)	⬇️
...fa/rpc/registry/consul/model/HeartbeatService.java	32.35% <0%> (+2.94%)	5% <0%> (+1%)	⬆️
...fa/rpc/registry/consul/internal/ConsulManager.java	51% <0%> (+5%)	13% <0%> (+2%)	⬆️
...ofa/rpc/registry/consul/internal/TtlScheduler.java	83.33% <0%> (+5.55%)	8% <0%> (+1%)	⬆️

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