Add Jib Core and CLI release checklists and update release workflows

[chanseokoh]

This auto-files a checklist issue when releasing Jib Core and Jib CLI.

[codecov]

Codecov Report

Merging #3175 (fcbc333) into master (1ea37ee) will increase coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3175      +/-   ##
============================================
+ Coverage     71.15%   71.19%   +0.03%     
- Complexity     2323     2331       +8     
============================================
  Files           279      279              
  Lines          9835     9848      +13     
  Branches        989      990       +1     
============================================
+ Hits           6998     7011      +13     
  Misses         2491     2491              
  Partials        346      346              

Impacted Files	Coverage Δ	Complexity Δ
...b/plugins/common/PluginConfigurationProcessor.java	64.08% <0.00%> (+0.20%)	65.00% <0.00%> (ø%)
...jib/plugins/common/JavaContainerBuilderHelper.java	95.45% <0.00%> (+0.90%)	21.00% <0.00%> (+8.00%)

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