Bump minimal julia version up to v1.6

As per JuliaPhysics#144 (comment),
to allow for `Symbolics` extension/integration.

Author: LebedevRI

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
       fail-fast: false
       matrix:
         julia-version:
-          - "1.0"
+          - "1.6"
           - "1"
           - "nightly"
         os:

Project.toml

@@ -28,7 +28,7 @@ MeasurementsUnitfulExt = "Unitful"
 Calculus = "0.4.1, 0.5"
 RecipesBase = "0.6.0, 0.7, 0.8, 1.0"
 Requires = "0.5.0, 1"
-julia = "1"
+julia = "1.6"
 
 [extras]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"