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

Author: CompatHelper Julia

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"
 ChainRulesCore = "0.9.7, 0.10, 1"