fix(github-release): update flux group to v2.1.2 (#976)

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

bootstrap/templates/kubernetes/bootstrap/kustomization.yaml.j2

@@ -4,7 +4,7 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-  - github.com/fluxcd/flux2/manifests/install?ref=v2.1.1
+  - github.com/fluxcd/flux2/manifests/install?ref=v2.1.2
 patches:
   # Remove the default network policies
   - patch: |-