chore(deps): bump cert-manager::devops-stack-module-cert-manager

Bumps [cert-manager::devops-stack-module-cert-manager](https://github.com/camptocamp/devops-stack-module-cert-manager) from 8.3.0 to 8.4.0.
- [Release notes](https://github.com/camptocamp/devops-stack-module-cert-manager/releases)
- [Changelog](https://github.com/camptocamp/devops-stack-module-cert-manager/blob/main/CHANGELOG.md)
- [Commits](camptocamp/devops-stack-module-cert-manager@v8.3.0...v8.4.0)

---
updated-dependencies:
- dependency-name: cert-manager::github::camptocamp/devops-stack-module-cert-manager::v8.3.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

examples/kind/main.tf

@@ -51,7 +51,7 @@ module "traefik" {
 }
 
 module "cert-manager" {
-  source = "git::https://github.com/camptocamp/devops-stack-module-cert-manager.git//self-signed?ref=v8.3.0"
+  source = "git::https://github.com/camptocamp/devops-stack-module-cert-manager.git//self-signed?ref=v8.4.0"
 
   argocd_project = local.cluster_name