[MacPorts] #29807: BibTool: update to 2.52 and fix livecheck

[MacPorts]

#29807: BibTool: update to 2.52 and fix livecheck
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 Reporter:  ryandesign@…             |       Owner:  tristan@…               
     Type:  update                   |      Status:  new                     
 Priority:  Normal                   |   Milestone:                          
Component:  ports                    |     Version:  1.9.2                   
 Keywords:                           |        Port:  BibTool                 
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 BibTool should be updated to 2.52. I'll attach a diff.

 The port's livecheck doesn't work either and should be fixed.

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Ticket URL: <https://trac.macports.org/ticket/29807>
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