Fix GH actions to commit binaries when merging PR to master

It is expected to be triggered with

Lines 68 to 69 in 29080f8

    
           - name: Push binaries 
        
             if: contains(matrix.os, 'latest') && contains(matrix.python-version, '3.9') && github.event.pull_request.merged == true

However, recent merge of PR #68 shows that this step is skipped, see https://github.com/lbl-srg/funnel/actions/runs/6165805051/job/16734235379

This issue is to fix the condition to trigger the push of the binaries when merging a PR to the master branch.

See https://github.com/orgs/community/discussions/26558#discussioncomment-3252329 for an explanation of why this issue occurred.

	- name: Push binaries
	if: contains(matrix.os, 'latest') && contains(matrix.python-version, '3.9') && github.event.pull_request.merged == true