maint: [network-agent] bump app to v0.0.23-alpha (#303)

## Which problem is this PR solving?

Updating network-agent chart to use newer app version.

## Short description of the changes

- Bump app version.
- Add more words to values.yaml about how headers will appear in data.

Co-authored-by: Jamie Danielson <jamiedanielson@honeycomb.io>

charts/network-agent/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: network-agent
 description: Honeycomb Network Agent
 version: 0.0.2
-appVersion: v0.0.22-alpha
+appVersion: v0.0.23-alpha
 home: https://honeycomb.io
 sources:
   - https://github.com/honeycombio/honeycomb-network-agent

charts/network-agent/values.yaml

@@ -34,5 +34,7 @@ extraEnvVars:
   # - name: INCLUDE_REQUEST_URL
   #   value: "false"
   # Configures the list of HTTP headers to be recorded from requests/responses.
+  # Headers will appear as attributes with names normalized to lower- and snake-case.
+  # For example: http.request.header.user_agent, http.response.header.x_custom_header
   # - name: HTTP_HEADERS
   #   value: "User-Agent,X-Custom-Header"