Only run aqua test on recent versions

MilesCranmer · MilesCranmer · commit 84de01c84809 · 2023-08-06T02:13:07.000-04:00
diff --git a/test/unittest.jl b/test/unittest.jl
@@ -1,6 +1,6 @@
 using SafeTestsets
 
-@safetestset "Test Aqua.jl" begin
+VERSION >= v"1.9" && @safetestset "Test Aqua.jl" begin
     include("test_aqua.jl")
 end
 
