Tests

`PartitionedGraphs` extension for `DataGraphs` and interface overhaul… #81

Job	Run time
Tests (1, ubuntu-latest) / Julia 1 - ubuntu-latest	1m 41s
Tests (1, windows-latest) / Julia 1 - windows-latest	6m 16s
Tests (1, macOS-latest) / Julia 1 - macOS-latest	1m 25s
Tests (lts, macOS-latest) / Julia lts - macOS-latest	3m 26s
Tests (lts, ubuntu-latest) / Julia lts - ubuntu-latest	2m 48s
Tests (lts, windows-latest) / Julia lts - windows-latest	2m 8s
	17m 44s

Provide feedback