Adding pull_request_target

[gagoar]

Issue Reference: fixes #102

Description

pull_request_target is a logical addition given that GitHub has recently added this event to deal with forks PRing to a base repo.

Motivation and Context

we need to support any form of PR action.

How Has This Been Tested?

unit tests.

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[github-actions]

Thanks for contributing!. The pull request description looks good. Please give us some time to review!

[codecov]

Codecov Report

Merging #103 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #103   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         6           
  Lines          266       266           
  Branches        48        48           
=========================================
  Hits           266       266           

Flag	Coverage Δ
#unittests	100.00% <ø> (ø)

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