bump julia 1.6 and in CI

Author: ablaom

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.5'
+          - '1.6'
           - '1'
         os:
           - ubuntu-latest

Project.toml

@@ -19,7 +19,7 @@ LinearMaps = "2.6, 3.2"
 MLJModelInterface = "0.3, 0.4, 1.0"
 Optim = "0.20, 0.21, 1"
 Parameters = "0.12"
-julia = "1.5"
+julia = "1.6"
 
 [extras]
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"