CompatHelper: bump compat for JSON to 1, (keep existing compat)

Author: CompatHelper Julia

Project.toml

@@ -77,7 +77,7 @@ ForwardDiff = "0.10"
 Graphs = "1"
 HypothesisTests = "0.11"
 Interpolations = "0.14, 0.15"
-JSON = "0.21"
+JSON = "0.21, 1"
 JuliaBUGS = "0.8, 0.9"
 LogDensityProblems = "2"
 LogDensityProblemsAD = "1"