Add --force flag to push command

[hypnoglow]

References #13

[codecov-io]

Codecov Report

Merging #35 into master will increase coverage by 18.32%.
The diff coverage is 79.31%.

@@             Coverage Diff             @@
##           master      #35       +/-   ##
===========================================
+ Coverage   38.46%   56.79%   +18.32%     
===========================================
  Files           3        3               
  Lines          52       81       +29     
===========================================
+ Hits           20       46       +26     
  Misses         30       30               
- Partials        2        5        +3

Impacted Files	Coverage Δ
internal/index/index.go	56.89% <79.31%> (+32.75%)	⬆️

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