Update Terraform flux to v1.6.3 (#88)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

terraform/k8s/cluster/providers.tf

@@ -16,7 +16,7 @@ terraform {
 
     flux = {
       source  = "fluxcd/flux"
-      version = "1.6.2"
+      version = "1.6.3"
     }
   }
 }