Rename 'gitops-system' namespace to 'gotk-system'

To align with the project name, and the group introduced in #236.

manifests/install/kustomization.yaml

@@ -1,6 +1,6 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
-namespace: gitops-system
+namespace: gotk-system
 resources:
   - namespace.yaml
   - ../bases/source-controller

manifests/install/labels.yaml

@@ -3,7 +3,7 @@ kind: LabelTransformer
 metadata:
   name: labels
 labels:
-  app.kubernetes.io/instance: gitops-system
+  app.kubernetes.io/instance: gotk-system
 fieldSpecs:
   - path: metadata/labels
     create: true

manifests/install/namespace.yaml

@@ -1,4 +1,4 @@
 apiVersion: v1
 kind: Namespace
 metadata:
-  name: gitops-system
+  name: gotk-system