Update FrankWolfe requirement to 0.6.4 in /test

Updates the requirements on [FrankWolfe](https://github.com/ZIB-IOL/FrankWolfe.jl) to permit the latest version.
- [Release notes](https://github.com/ZIB-IOL/FrankWolfe.jl/releases)
- [Commits](ZIB-IOL/FrankWolfe.jl@v0.1.0...v0.6.4)

---
updated-dependencies:
- dependency-name: FrankWolfe
  dependency-version: 0.6.4
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

test/Project.toml

@@ -28,6 +28,7 @@ Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 InferOpt = {path = ".."}
 
 [compat]
+FrankWolfe = "0.6.4"
 GridGraphs = "0.10"
 JuliaFormatter = "1"
 Test = "1"