Updating packages in 0.7 fails

Hello,
I have the following error when I try to update my packages:

ufechner@tuxedo:~$ julia7
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.7.0 (2018-08-08 06:46 UTC)
 _/ |\__'_|_|_|\__'_|  |  Official http://julialang.org/ release
|__/                   |  x86_64-pc-linux-gnu

(v0.7) pkg> up
  Updating registry at `~/.julia/registries/General`
  Updating git-repo `https://github.com/JuliaRegistries/General.git`
  Updating git-repo `https://github.com/ModiaSim/Modia.jl.git`
  Updating git-repo `https://github.com/JuliaOpt/JuMP.jl.git`
  Updating git-repo `https://github.com/ModiaSim/ModiaMath.jl.git`
  Updating git-repo `https://github.com/JuliaPlots/Makie.jl.git`
  Updating git-repo `https://github.com/JuliaPlots/AbstractPlotting.jl.git`
  Updating git-repo `https://github.com/JuliaGL/GLFW.jl.git`
 Resolving package versions...
  Updating `~/.julia/environments/v0.7/Project.toml`
 [no changes]
  Updating `~/.julia/environments/v0.7/Manifest.toml`
 [no changes]
ERROR: MethodError: no method matching getindex(::Nothing, ::String)
Stacktrace:
 [1] #build_versions#45(::Bool, ::Function, ::Pkg.Types.Context, ::Array{Base.UUID,1}) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/Operations.jl:1016
 [2] build_versions at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/Operations.jl:1005 [inlined]
 [3] up(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/Operations.jl:1209
 [4] #up#31(::Pkg.Types.UpgradeLevel, ::Pkg.Types.PackageMode, ::Bool, ::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Function, ::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/API.jl:184
 [5] up at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/API.jl:158 [inlined]
 [6] do_up!(::Dict{Symbol,Any}, ::Array{Pkg.Types.PackageSpec,1}, ::Dict{Symbol,Any}) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/REPLMode.jl:610
 [7] #invokelatest#1(::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Function, ::Any, ::Any, ::Vararg{Any,N} where N) at ./essentials.jl:691
 [8] invokelatest(::Any, ::Any, ::Vararg{Any,N} where N) at ./essentials.jl:690
 [9] do_cmd!(::Pkg.REPLMode.PkgCommand, ::REPL.LineEditREPL) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/REPLMode.jl:542
 [10] #do_cmd#30(::Bool, ::Function, ::REPL.LineEditREPL, ::String) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/REPLMode.jl:507
 [11] do_cmd at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/REPLMode.jl:503 [inlined]
 [12] (::getfield(Pkg.REPLMode, Symbol("##41#44")){REPL.LineEditREPL,REPL.LineEdit.Prompt})(::REPL.LineEdit.MIState, ::Base.GenericIOBuffer{Array{UInt8,1}}, ::Bool) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/Pkg/src/REPLMode.jl:842
 [13] #invokelatest#1 at ./essentials.jl:691 [inlined]
 [14] invokelatest at ./essentials.jl:690 [inlined]
 [15] run_interface(::REPL.Terminals.TextTerminal, ::REPL.LineEdit.ModalInterface, ::REPL.LineEdit.MIState) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/REPL/src/LineEdit.jl:2261
 [16] run_frontend(::REPL.LineEditREPL, ::REPL.REPLBackendRef) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/REPL/src/REPL.jl:1029
 [17] run_repl(::REPL.AbstractREPL, ::Any) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v0.7/REPL/src/REPL.jl:191
 [18] (::getfield(Base, Symbol("##831#833")){Bool,Bool,Bool,Bool})(::Module) at ./logging.jl:311
 [19] #invokelatest#1 at ./essentials.jl:691 [inlined]
 [20] invokelatest at ./essentials.jl:690 [inlined]
 [21] macro expansion at ./logging.jl:308 [inlined]
 [22] run_main_repl(::Bool, ::Bool, ::Bool, ::Bool, ::Bool) at ./client.jl:340
 [23] exec_options(::Base.JLOptions) at ./client.jl:252
 [24] _start() at ./client.jl:432

(v0.7) pkg> 

Any idea?