Update GeometryOptimization requirement to 0.1.5 in /docs (#51)

Updates the requirements on [GeometryOptimization](https://github.com/JuliaMolSim/GeometryOptimization.jl) to permit the latest version.
- [Release notes](https://github.com/JuliaMolSim/GeometryOptimization.jl/releases)
- [Commits](v0.0.1...v0.1.5)

---
updated-dependencies:
- dependency-name: GeometryOptimization
  dependency-version: 0.1.5
  dependency-type: direct:production
...

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docs/Project.toml

@@ -27,6 +27,7 @@ AtomsIO = "0.3.1"
 DFTK = "0.7"
 Documenter = "~1.8, 1.16"
 EmpiricalPotentials = "0.2.5"
+GeometryOptimization = "0.1.5"
 PseudoPotentialData = "0.2"
 Unitful = "1.28.0"
 UnitfulAtomic = "1.0.0"