(v1.3) pkg> add .
  Updating git-repo `/home/scheme/DiffEqTutorials.jl`
  Updating git-repo `/home/scheme/DiffEqTutorials.jl`
 Resolving package versions...
ERROR: Unsatisfiable requirements detected for package Gadfly [c91e804a]:
 Gadfly [c91e804a] log:
 ├─possible versions are: [0.8.0, 1.0.0-1.0.1, 1.1.0] or uninstalled
 ├─restricted to versions 1.1.0-1 by DiffEqTutorials [6d1b261a], leaving only versions 1.1.0
 │ └─DiffEqTutorials [6d1b261a] log:
 │   ├─possible versions are: 0.2.1 or uninstalled
 │   └─DiffEqTutorials [6d1b261a] is fixed to version 0.2.1
 └─restricted by compatibility requirements with Distributions [31c24e10] to versions: [0.8.0, 1.0.0-1.0.1] or uninstalled — no versions left
   └─Distributions [31c24e10] log:
     ├─possible versions are: [0.16.0-0.16.4, 0.17.0, 0.18.0, 0.19.1-0.19.2, 0.20.0, 0.21.0-0.21.3, 0.21.5-0.21.12] or uninstalled
     ├─restricted to versions 0.21 by DiffEqSensitivity [41bf760c], leaving only versions [0.21.0-0.21.3, 0.21.5-0.21.12]
     │ └─DiffEqSensitivity [41bf760c] log:
     │   ├─possible versions are: 6.1.0 or uninstalled
     │   └─DiffEqSensitivity [41bf760c] is fixed to version 6.1.0
     └─restricted by compatibility requirements with SpecialFunctions [276daf66] to versions: [0.16.0-0.16.4, 0.17.0, 0.18.0, 0.19.1-0.19.2, 0.21.11-0.21.12] or uninstalled, leaving only versions: 0.21.11-0.21.12
       └─SpecialFunctions [276daf66] log:
         ├─possible versions are: [0.7.0-0.7.2, 0.8.0, 0.9.0] or uninstalled
         └─restricted to versions 0.9.0 by an explicit requirement, leaving only versions 0.9.0