fix: processing of strategy.matrix.include (#1200)

* Update workflow.go

* Update workflow.go

* Update workflow.go

* Update workflow.go

* Update workflow.go

* Update workflow.go

* Add Tests

* Update workflow.go

* Modify Test

* use tabs

Co-authored-by: Casey Lee <cplee@nektos.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/model/workflow_test.go

@@ -247,6 +247,7 @@ func TestReadWorkflow_Strategy(t *testing.T) {
 			{"datacenter": "site-c", "node-version": "14.x", "site": "staging"},
 			{"datacenter": "site-c", "node-version": "16.x", "site": "staging"},
 			{"datacenter": "site-d", "node-version": "16.x", "site": "staging"},
+			{"php-version": 5.4},
 			{"datacenter": "site-a", "node-version": "10.x", "site": "prod"},
 			{"datacenter": "site-b", "node-version": "12.x", "site": "dev"},
 		},