fix: add resource requests/limits to init-sysctl containers (#220)

Fix for warnings from validating admission policies:

```
❯ skd s4s2 frontend
sentry-kube -C s4s2 -q diff frontend
Rendering services: frontend
Waiting on kubectl diff.

Warning: Validation failed for ValidatingAdmissionPolicy 'cpu-resource-policy' with binding 'cpu-resource-policy-binding': frontend-default: all containers must have CPU requests set. Missing: init-sysctl

Warning: Validation failed for ValidatingAdmissionPolicy 'memory-resource-policy' with binding 'memory-resource-policy-binding': frontend-default: memory request should equal memory limit (https://home.robusta.dev/blog/kubernetes-memory-limit). Offending: init-sysctl

Warning: Validation failed for ValidatingAdmissionPolicy 'cpu-resource-policy' with binding 'cpu-resource-policy-binding': frontend-default-production-canary: all containers must have CPU requests set. Missing: init-sysctl

Warning: Validation failed for ValidatingAdmissionPolicy 'memory-resource-policy' with binding 'memory-resource-policy-binding': frontend-default-production-canary: memory request should equal memory limit (https://home.robusta.dev/blog/kubernetes-memory-limit). Offending: init-sysctl
```

Resource usage for these containers is quite low:

Max mem is 10% of limit set here:

<img width="2552" height="324" alt="image"
src="https://github.com/user-attachments/assets/f9fa3c1c-f047-4851-aaf4-cd598fc8afbf"
/>

Max CPU is well under 50m (note y-axis scale is **micro**cores, not
millicores here), and it would be burstable anyways:

<img width="2580" height="336" alt="image"
src="https://github.com/user-attachments/assets/c5680716-3d37-4960-af71-7eec50d049e4"
/>

Author: mwarkentin

libsentrykube/ext.py

@@ -809,6 +809,10 @@ def run(self, params: dict):
                 "image": "alpine:3.19",
                 "securityContext": {"privileged": True},
                 "command": ["sh", "-c", command],
+                "resources": {
+                    "requests": {"cpu": "50m", "memory": "64Mi"},
+                    "limits": {"memory": "64Mi"},
+                },
             }
         )