Change deploy workflow to run on PRs only with [push image] message

[viepovsky]

Docker image is only build and pushed when

• it is a push to master
• on PR when commit head message contains [push image]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (bd5b3ef) 75.75% compared to head (baff383) 75.75%.
Report is 1 commits behind head on master.

❗ Current head baff383 differs from pull request most recent head 09a8414. Consider uploading reports for the commit 09a8414 to get more accurate results

Additional details and impacted files

@@            Coverage Diff            @@
##             master      #16   +/-   ##
=========================================
  Coverage     75.75%   75.75%           
  Complexity      425      425           
=========================================
  Files            83       83           
  Lines          1266     1266           
  Branches         24       24           
=========================================
  Hits            959      959           
  Misses          289      289           
  Partials         18       18           

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