Add ecbundle-merge to setup.py scripts

[pardallio]

On #46 I forgot to add ecbundle-merge to setup.py so it is still not available from pip.

Description

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 49.26%. Comparing base (de8a72c) to head (d3ba85b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #49      +/-   ##
==========================================
+ Coverage   49.20%   49.26%   +0.05%     
==========================================
  Files          51       51              
  Lines       10385    10410      +25     
==========================================
+ Hits         5110     5128      +18     
- Misses       5275     5282       +7     

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[wdeconinck]

@pardallio sorry I missed this, can you redirect to develop instead of main?