Upd: upgrade package version

[gaoxinge]

What this PR does:

• update package version by following Raise the version of consul and client-go #656
  • github.com/hashicorp/consul to v1.8.0
  • github.com/hashicorp/consul/api to v1.5.0
  • k8s.io/api to v0.16.9
  • k8s.io/apimachinery to v0.16.9
  • k8s.io/client-go to v0.16.9
• make etcd client codes more simple and clean
• decrease the stack level of logger, so logger.Warnf will not show stack trace info

Which issue(s) this PR fixes:

Fixes #656.

Special notes for your reviewer:

• NONE

Does this PR introduce a user-facing change?:

NONE

[codecov-commenter]

Codecov Report

Merging #672 into develop will decrease coverage by 0.02%.
The diff coverage is 74.13%.

@@             Coverage Diff             @@
##           develop     #672      +/-   ##
===========================================
- Coverage    63.80%   63.77%   -0.03%     
===========================================
  Files          236      237       +1     
  Lines        12313    12298      -15     
===========================================
- Hits          7856     7843      -13     
- Misses        3690     3701      +11     
+ Partials       767      754      -13     

Impacted Files	Coverage Δ
cluster/cluster_impl/available_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/broadcast_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/broadcast_cluster_invoker.go	80.00% <ø> (ø)
cluster/cluster_impl/failback_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/failback_cluster_invoker.go	78.02% <ø> (-2.20%)	⬇️
cluster/cluster_impl/failfast_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/failfast_cluster_invoker.go	71.42% <ø> (ø)
cluster/cluster_impl/failover_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/failsafe_cluster.go	100.00% <ø> (ø)
cluster/cluster_impl/failsafe_cluster_invoker.go	81.81% <ø> (ø)
... and 55 more

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