BuildEvent BuildDuration is a float (#203)

* Fix the PipelineEvent struct, with proper sub struct for Runner and correct type for the artifacts_file 'size' field

* Updated tests for changes to PipelineEvent

* Formatting

* Naming

* BuildEvent BuildDuration is a float, not a string

* float64

events.go

@@ -538,7 +538,7 @@ type BuildEvent struct {
 	BuildStatus       string  `json:"build_status"`
 	BuildStartedAt    string  `json:"build_started_at"`
 	BuildFinishedAt   string  `json:"build_finished_at"`
-	BuildDuration     string `json:"build_duration"`
+	BuildDuration     float64 `json:"build_duration"`
 	BuildAllowFailure bool    `json:"build_allow_failure"`
 	ProjectID         int     `json:"project_id"`
 	ProjectName       string  `json:"project_name"`

events_test.go

@@ -391,7 +391,7 @@ func TestBuildEventUnmarshal(t *testing.T) {
   "build_status": "created",
   "build_started_at": null,
   "build_finished_at": null,
-  "build_duration": null,
+  "build_duration": 23.265997,
   "build_allow_failure": false,
   "project_id": 380,
   "project_name": "gitlab-org/gitlab-test",