Switch Actions organization from ecmwf-actions to ecmwf

[recmanj]

Update CI/CD workflows as ecmwf-actions actions have been moved to ecmwf organization.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.68%. Comparing base (2455719) to head (45f6792).
Report is 5 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop      #37   +/-   ##
========================================
  Coverage    98.68%   98.68%           
========================================
  Files            8        8           
  Lines          684      684           
  Branches        26       26           
========================================
  Hits           675      675           
  Misses           7        7           
  Partials         2        2           

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