changed node exporter limit and request to 250Mi

changes default memory limits for node exporter pods from 50Mi to 250Mi

relates to #79 (closed)

chart/Chart.yaml

@@ -23,7 +23,7 @@ name: kube-prometheus-stack
 sources:
   - https://github.com/prometheus-community/helm-charts
   - https://github.com/prometheus-operator/kube-prometheus
-version: 35.5.1-bb.3
+version: 35.5.1-bb.4
 appVersion: 0.57.0
 kubeVersion: ">=1.16.0-0"
 home: https://github.com/prometheus-operator/kube-prometheus