Add method and subpath flags to timetrigger object for triggering a function (#3017)

* Update timetrigger crd and add method and subpath fields in spec.
Update fission-cli to accept user input for method and subpath fields.
Update publisher package to utilize these fields for triggering a function.
Update timer controller to use method and subpath fields for publishing a request.
Add a new test TestPublisherSubpath in pulisher package.

Signed-off-by: Md Soharab Ansari <soharab.ansari@infracloud.io>

* Use kubebuilder default annotation.
Update test for fission-cli timetrigger create, update command to support method and subpath flags.

Signed-off-by: Md Soharab Ansari <soharab.ansari@infracloud.io>

---------

Signed-off-by: Md Soharab Ansari <soharab.ansari@infracloud.io>

pkg/kubewatcher/kubewatcher.go

@@ -22,6 +22,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"net/http"
 	"reflect"
 	"strings"
 	"sync/atomic"
@@ -268,7 +269,7 @@ func (ws *watchSubscription) eventDispatchLoop(ctx context.Context) {
 		// the triggers can only be created in the same namespace as the function.
 		// so essentially, function namespace = trigger namespace.
 		url := utils.UrlForFunction(ws.watch.Spec.FunctionReference.Name, ws.watch.ObjectMeta.Namespace)
-		ws.publisher.Publish(ctx, buf.String(), headers, url)
+		ws.publisher.Publish(ctx, buf.String(), headers, http.MethodPost, url)
 	}
 }