[newrelic-logging]: Bump chart to 1.39.0 / appVersion 3.7.0

## Summary                           
- Bump chart version to 1.39.0
- Bump appVersion to 3.7.0 (Fluent Bit 5.0.8 Linux / 5.0.6 Windows)
- Update image test assertions
Related: newrelic/newrelic-fluent-bit-output#261

Author: likitha-maddikara

charts/newrelic-logging/Chart.yaml

@@ -1,8 +1,8 @@
 apiVersion: v2
 description: A Helm chart to deploy New Relic Kubernetes Logging as a DaemonSet, supporting both Linux and Windows nodes and containers
 name: newrelic-logging
-version: 1.38.3
-appVersion: 3.6.0
+version: 1.39.0
+appVersion: 3.7.0
 home: https://github.com/newrelic/kubernetes-logging
 icon: https://newrelic.com/assets/newrelic/source/NewRelic-logo-square.svg
 maintainers:

charts/newrelic-logging/tests/images_test.yaml

@@ -17,16 +17,16 @@ tests:
     asserts:
       - equal:
           path: spec.template.spec.containers[0].image
-          value: docker.io/newrelic/newrelic-fluentbit-output:3.6.0
+          value: docker.io/newrelic/newrelic-fluentbit-output:3.7.0
         template: templates/daemonset.yaml
       - equal:
           path: spec.template.spec.containers[0].image
-          value: docker.io/newrelic/newrelic-fluentbit-output:3.6.0-windows-ltsc-2019
+          value: docker.io/newrelic/newrelic-fluentbit-output:3.7.0-windows-ltsc-2019
         template: templates/daemonset-windows.yaml
         documentIndex: 0
       - equal:
           path: spec.template.spec.containers[0].image
-          value: docker.io/newrelic/newrelic-fluentbit-output:3.6.0-windows-ltsc-2022
+          value: docker.io/newrelic/newrelic-fluentbit-output:3.7.0-windows-ltsc-2022
         template: templates/daemonset-windows.yaml
         documentIndex: 1
   - it: global registry is used if set