fix github_output syntax on GHA

[mirpedrol]

Fix the syntax of github_output on GitHub actions in the pipeline template.

PR checklist

• This comment contains a description of changes (with reason)
• CHANGELOG.md is updated
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

[codecov]

Codecov Report

Merging #2114 (78d4a25) into dev (f8eab49) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev    #2114   +/-   ##
=======================================
  Coverage   67.97%   67.97%           
=======================================
  Files          43       43           
  Lines        5633     5633           
=======================================
  Hits         3829     3829           
  Misses       1804     1804           

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