CompatHelper: bump compat for AbstractPPL to 0.4, (keep existing compat) (#349)

This pull request changes the compat entry for the `AbstractPPL` package from `0.3` to `0.3, 0.4`.
This keeps the compat entries for earlier versions.



Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

Co-authored-by: Hong Ge <[email protected]>

Author: github-actions[bot]

Project.toml

@@ -18,7 +18,7 @@ ZygoteRules = "700de1a5-db45-46bc-99cf-38207098b444"
 
 [compat]
 AbstractMCMC = "2, 3.0"
-AbstractPPL = "0.3"
+AbstractPPL = "0.3, 0.4"
 BangBang = "0.3"
 Bijectors = "0.5.2, 0.6, 0.7, 0.8, 0.9, 0.10"
 ChainRulesCore = "0.9.7, 0.10, 1"