add workflow "stale"

[hasezoey]

• add github workflow "stale"

settings:

• runs once every day
• runs only on these tags: question,can't reproduce,Needs More Information,needs repro script,stale
• definitely doesnt run on these tags: help wanted,docs,enhancement,feature,dependencies
• marks issues as stale if there is no activity in 60 days
• closes issues when the date tagging with stale is older than 7 days
• removes stale tag on activity

[codecov]

Codecov Report

Merging #354 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #354   +/-   ##
=======================================
  Coverage   78.73%   78.73%           
=======================================
  Files           9        9           
  Lines         931      931           
  Branches      266      266           
=======================================
  Hits          733      733           
  Misses        196      196           
  Partials        2        2           

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[nodkz]

Thanks a lot! Amazing tool!