fix: allow test within pact.Verify() to fail build

pact.Verify(integrationTest) currently only fails
if the pact verification fails, but integration
tests within it may also do so.

Fixes #37

Author: mefellows

Diff for: README.md

@@ -249,7 +249,7 @@ Read more about [flexible matching](https://github.com/realestate-com-au/pact/wi
 				]
 			]`)
 	})
-	go http.ListenAndServe(":8000"), mux)
+	go http.ListenAndServe(":8000", mux)
 	```
 
 	Note that the server has 2 endpoints: `/states` and `/setup` that allows the

Diff for: dsl/pact.go

@@ -179,10 +179,13 @@ func (p *Pact) Verify(integrationTest func() error) error {
 	}
 
 	// Run the integration test
-	integrationTest()
+	err := integrationTest()
+	if err != nil {
+		return err
+	}
 
 	// Run Verification Process
-	err := mockServer.Verify()
+	err = mockServer.Verify()
 	if err != nil {
 		return err
 	}