Fix v7 ecosystem compat gap: widen DiffEqBase to allow v7

`DiffEqBase = "6.189.1"` was capped at v6, causing the resolver to
pick the v6 ecosystem (DiffEqBase v6, SciMLBase v2) and fail at
`LateBindingUpdateU0PContext` in MTKBase precompile.

Changed `DiffEqBase = "6.189.1"` → `"6.189.1, 7"` so the resolver
can pick DiffEqBase v7.0.0, which pulls SciMLBase v3.6.0 and the
full v7 SciML ecosystem consistent with the OrdinaryDiffEq v7 compat
already present.

Verified by Manifest resolution: DiffEqBase v7.0.0, SciMLBase v3.6.0.

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

Author: ChrisRackauckas

Project.toml

@@ -19,7 +19,7 @@ ChainRulesCore = "1.24"
 ControlSystemsBase = "1.4"
 DataFrames = "1.7"
 DataInterpolations = "8"
-DiffEqBase = "6.189.1"
+DiffEqBase = "6.189.1, 7"
 ForwardDiff = "0.10, 1"
 IfElse = "0.1"
 LinearAlgebra = "1.10"