ci(Tests): run test with depwarn set to yes

All the deprecations in the package itself have been appropriately
fixed up.
However, currently, tests fail when `depwarn` is set to error because of
a transitive dependency's depwarn, which is not directly influenced by
the package's primitives itself.

```julia
WARNING: using deprecated binding Colors.RGB1 in PlotUtils.
, use XRGB instead.
PlotUtils.RGB1 is deprecated, use ColorTypes.XRGB{T} where T<:Union{AbstractFloat, FixedPointNumbers.FixedPoint{T, f} where f where T<:Integer} instead.

WARNING: using deprecated binding Colors.RGB4 in PlotUtils.
, use RGBX instead.
PlotUtils.RGB4 is deprecated, use ColorTypes.RGBX{T} where T<:Union{AbstractFloat, FixedPointNumbers.FixedPoint{T, f} where f where T<:Integer} instead.
```

Thus, set `depwarn` to just `yes` while runnning the julia tests, so
that CI can pass.

Author: thazhemadam

.github/workflows/Tests.yml

@@ -24,4 +24,5 @@ jobs:
     uses: "SciML/.github/.github/workflows/tests.yml@v1"
     with:
       julia-version: "${{ matrix.version }}"
+      julia-runtest-depwarn: "yes"
     secrets: "inherit"