Fixes step encoding in logcli.

[cyriltovena]

The step.Seconds float was casted into a int making it impossible to go sub second.

Fixes #3318

[codecov-io]

Codecov Report

Merging #3325 (03e5678) into master (82cead2) will increase coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #3325      +/-   ##
==========================================
+ Coverage   62.59%   62.60%   +0.01%     
==========================================
  Files         201      201              
  Lines       17144    17144              
==========================================
+ Hits        10731    10733       +2     
+ Misses       5450     5449       -1     
+ Partials      963      962       -1     

Impacted Files	Coverage Δ
pkg/logcli/client/client.go	5.50% <0.00%> (ø)
pkg/querier/queryrange/limits.go	91.66% <0.00%> (-4.17%)	⬇️
pkg/logql/evaluator.go	90.19% <0.00%> (+0.35%)	⬆️
pkg/promtail/targets/file/tailer.go	75.00% <0.00%> (+1.78%)	⬆️