Gitlab webhook for multiple event types

[rossigee]

Is your feature request related to a problem? Please describe.
Currently, we can only configure a Gitlab webhook for one specific event type.

Describe the solution you'd like
I'd like to be able to configure a webhook that accepts all the event types.

Describe alternatives you've considered
N/A

Additional context
Gitlab's API and the upstream 'go-gitlab' library seem to allow you to specify multiple events by passing 'true' for multiple boolean event type attributes...

https://github.com/xanzy/go-gitlab/blob/bf34eca5d13a9f4c3f501d8a97b8ac226d55e4d9/projects.go#L794

So, we need something like this...

diff --git a/pkg/apis/eventsources/v1alpha1/types.go b/pkg/apis/eventsources/v1alpha1/types.go
index bb2817e..134a348 100644
--- a/pkg/apis/eventsources/v1alpha1/types.go
+++ b/pkg/apis/eventsources/v1alpha1/types.go
@@ -376,9 +376,9 @@ type GitlabEventSource struct {
        Webhook *webhook.Context `json:"webhook" protobuf:"bytes,1,name=webhook"`
        // ProjectId is the id of project for which integration needs to setup
        ProjectId string `json:"projectId" protobuf:"bytes,2,name=projectId"`
-       // Event is a gitlab event to listen to.
+       // Events are which gitlab events to listen to.
        // Refer https://github.com/xanzy/go-gitlab/blob/bf34eca5d13a9f4c3f501d8a97b8ac226d55e4d9/projects.go#L794.
-       Event string `json:"event" protobuf:"bytes,3,name=event"`
+       Events []string `json:"event" protobuf:"bytes,3,name=event"`
        // AccessToken is reference to k8 secret which holds the gitlab api access information
        AccessToken *corev1.SecretKeySelector `json:"accessToken" protobuf:"bytes,4,name=accessToken"`
        // EnableSSLVerification to enable ssl verification

[VaibhavPage]

It will be added in v0.16.0