Bump compat for DiffEqBase v7 / SciMLBase v3 ecosystem

Widen DiffEqBase compat from "6.122" to "6.122, 7" to allow the v7
ecosystem (DiffEqBase v7, SciMLBase v3, RecursiveArrayTools v4).
No source changes needed: all APIs used (DiffEqBase.__solve,
build_solution, AbstractODEAlgorithm, AbstractODEProblem, Stats)
remain available in v7 (Stats aliased to SciMLBase.DEStats).

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>

Author: ChrisRackauckas

Project.toml

@@ -10,7 +10,7 @@ PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 
 [compat]
-DiffEqBase = "6.122"
+DiffEqBase = "6.122, 7"
 JET = "0.9, 0.10, 0.11"
 MATLAB = "0.8, 0.9"
 ModelingToolkit = "8, 9, 10, 11"