Bump docs compat

Author: avik-pal

.buildkite/pipeline.yml

@@ -27,6 +27,7 @@ steps:
         using Pkg
         Pkg.instantiate()
         Pkg.activate("docs")
+        Pkg.develop(PackageSpec(path=pwd()))
         Pkg.instantiate()
         push!(LOAD_PATH, @__DIR__)
         println("+++ :julia: Building documentation")

docs/Project.toml

@@ -41,7 +41,7 @@ CSV = "0.10"
 ComponentArrays = "0.13, 0.14, 0.15"
 DataDeps = "0.7"
 DataFrames = "1"
-DiffEqFlux = "2"
+DiffEqFlux = "3"
 DifferentialEquations = "7.6.0"
 Distances = "0.10.7"
 Distributions = "0.25.78"