feat: add per-container resource configuration for runner and DinD #160 (#168)

This a correction that is forf from original work of [anders.eficode](https://gitea.com/anders.eficode) on [pull request #160](https://gitea.com/gitea/helm-actions/pulls/160)
Description of the change
Adds statefulset.dind.resources and statefulset.runner.resources as optional per-container resource overrides. When set, each takes precedence over the shared statefulset.resources for that container. When unset (default {}), statefulset.resources is used as before.

Benefits
The DinD sidecar and the runner container have very different resource profiles — DinD is memory-hungry (image layer cache, concurrent builds, image pulls) while the runner is a lightweight coordinator that is mostly idle between jobs. Separate resource limits allow right-sizing each container independently, avoiding the choice between over-provisioning the runner or under-provisioning DinD.

Possible drawbacks
None. Fully backward-compatible — both new values default to {}, causing the shared statefulset.resources fallback to apply exactly as before.

Checklist
- [x] Parameters are documented in the `values.yaml` and added to the `README.md` using [readme-generator-for-helm](https://github.com/bitnami-labs/readme-generator-for-helm)
- [x] Breaking changes are documented in the `README.md`
- [x] Helm templating unittests are added (required when changing anything in `templates` folder)
- [x] Bash unittests are added (required when changing anything in `scripts` folder)
- [x] All added template resources MUST render a namespace in metadata

---------

Co-authored-by: Le Prévost-Corvellec Arnault <arnault.le.prevost.corvellec@carbon-it.com>
Co-authored-by: Anders <lantzanders@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-actions/pulls/168
Reviewed-by: DaanSelen <135789+daanselen@noreply.gitea.com>
Co-authored-by: Arnault_LPC <194310+arnault_lpc@noreply.gitea.com>

unittests/helm/statefulset.yaml

@@ -451,3 +451,85 @@ tests:
       - equal:
           path: spec.template.spec.initContainers[0].image
           value: test.io/busybox:1.37.0
+
+#
+## RESOURCES
+#
+
+  - it: shared statefulset.resources applies to both runner and dind containers
+    template: templates/statefulset.yaml
+    set:
+      enabled: true
+      statefulset.resources:
+        requests:
+          memory: "512Mi"
+          cpu: "250m"
+        limits:
+          memory: "1Gi"
+    asserts:
+      - hasDocuments:
+          count: 1
+      - equal:
+          path: spec.template.spec.containers[0].resources
+          value:
+            requests:
+              memory: "512Mi"
+              cpu: "250m"
+            limits:
+              memory: "1Gi"
+      - equal:
+          path: spec.template.spec.initContainers[1].resources
+          value:
+            requests:
+              memory: "512Mi"
+              cpu: "250m"
+            limits:
+              memory: "1Gi"
+
+  - it: statefulset.runner.resources overrides shared resources for runner container only
+    template: templates/statefulset.yaml
+    set:
+      enabled: true
+      statefulset.resources:
+        requests:
+          memory: "512Mi"
+      statefulset.runner.resources:
+        requests:
+          memory: "256Mi"
+    asserts:
+      - hasDocuments:
+          count: 1
+      - equal:
+          path: spec.template.spec.containers[0].resources
+          value:
+            requests:
+              memory: "256Mi"
+      - equal:
+          path: spec.template.spec.initContainers[1].resources
+          value:
+            requests:
+              memory: "512Mi"
+
+  - it: statefulset.dind.resources overrides shared resources for dind container only
+    template: templates/statefulset.yaml
+    set:
+      enabled: true
+      statefulset.resources:
+        requests:
+          memory: "512Mi"
+      statefulset.dind.resources:
+        requests:
+          memory: "4Gi"
+    asserts:
+      - hasDocuments:
+          count: 1
+      - equal:
+          path: spec.template.spec.containers[0].resources
+          value:
+            requests:
+              memory: "512Mi"
+      - equal:
+          path: spec.template.spec.initContainers[1].resources
+          value:
+            requests:
+              memory: "4Gi"