Bump AbstractPPL to 0.12

[penelopeysm]

No description provided.

[github-actions]

Turing.jl documentation for PR #2614 is available at:
https://TuringLang.github.io/Turing.jl/previews/PR2614/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.60%. Comparing base (abbec12) to head (d532e22).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2614   +/-   ##
=======================================
  Coverage   85.60%   85.60%           
=======================================
  Files          22       22           
  Lines        1459     1459           
=======================================
  Hits         1249     1249           
  Misses        210      210           

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[coveralls]

Pull Request Test Coverage Report for Build 16150086267

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 85.665%

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Totals
Change from base Build 16127199312:	0.0%
Covered Lines:	1249
Relevant Lines:	1458

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💛 - Coveralls

[penelopeysm]

closes #2609
closes #2610