chore: move cluster into 'kubernetes/main' folder

.github/renovate.json5

@@ -15,17 +15,17 @@
   //"schedule": ["on saturday"],
   "flux": {
     "fileMatch": [
-      "(^|/)cluster/.+\\.ya?ml(\\.j2)?$"
+      "(^|/)kubernetes/.+/.+\\.ya?ml(\\.j2)?$"
     ]
   },
   "helm-values": {
     "fileMatch": [
-      "(^|/)cluster/.+\\.ya?ml(\\.j2)?$"
+      "(^|/)kubernetes/.+/.+\\.ya?ml(\\.j2)?$"
     ]
   },
   "kubernetes": {
     "fileMatch": [
-      "(^|/)cluster/.+\\.ya?ml(\\.j2)?$"
+      "(^|/)kubernetes/.+/.+\\.ya?ml(\\.j2)?$"
     ]
   },
   "kustomize": {