add stale bot configuration

[nobodyiam]

No description provided.

[coveralls]

Coverage increased (+0.02%) to 54.058% when pulling 20c2db3 on nobodyiam:add-stale-bot into 5daa088 on ctripcorp:master.

[codecov-io]

Codecov Report

Merging #2790 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #2790      +/-   ##
============================================
+ Coverage     50.45%   50.48%   +0.02%     
  Complexity     2084     2084              
============================================
  Files           413      413              
  Lines         12666    12666              
  Branches       1294     1294              
============================================
+ Hits           6391     6394       +3     
+ Misses         5821     5819       -2     
+ Partials        454      453       -1

Impacted Files	Coverage Δ	Complexity Δ
...mework/apollo/portal/component/PortalSettings.java	69.84% <0%> (+4.76%)	5% <0%> (ø)	⬇️

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