update to memento v0.7 (#299)

removes depreciation warnings.

Author: ccoffrin

CHANGELOG.md

@@ -2,7 +2,7 @@ PowerModels.jl Change Log
 =================
 
 ### Staged
-- nothing
+- Removed Memento depreciation warnings
 
 ### v0.7.1
 - Added warning when data is missing in a PTI file

REQUIRE

@@ -4,4 +4,4 @@ InfrastructureModels 0.0.6 0.2-
 MathProgBase 0.5.4
 JuMP 0.17 0.19-
 Compat 0.26.0
-Memento 0.6
+Memento 0.7

src/PowerModels.jl

@@ -18,7 +18,7 @@ const LOGGER = getlogger(@__MODULE__)
 # NOTE: If this line is not included then the precompiled `PowerModels.LOGGER` won't be registered at runtime.
 function __init__()
     Memento.register(LOGGER)
-    Memento.config(LOGGER, "info")
+    Memento.config!(LOGGER, "info")
 end
 
 include("io/matpower.jl")