fix content-type of geoserver service-config.json.template (#442)

## Overview

The `/geoserver` endpoint redirects to the HTML web view of the service.
Fix the indicated media-type of `type` for that endpoint in the service definition.

## Changes

**Non-breaking changes**
- fix content-type of GeoServer `service-config.json.template`

**Breaking changes**
- n/a

## Related Issue / Discussion

- n/a

CHANGES.md

@@ -15,7 +15,8 @@
 [Unreleased](https://github.com/bird-house/birdhouse-deploy/tree/master) (latest)
 ------------------------------------------------------------------------------------------------------------------
 
-[//]: # (list changes here, using '-' for each new entry, remove this when items are added)
+## Fixes
+- GeoServer: fix invalid media-type specified for the service's endpoint in `service-config.json.template`
 
 [2.1.2](https://github.com/bird-house/birdhouse-deploy/tree/2.1.2) (2024-03-25)
 ------------------------------------------------------------------------------------------------------------------

birdhouse/components/geoserver/service-config.json.template

@@ -11,7 +11,7 @@
  "links": [
  {
  "rel": "service",
- "type": "application/json",
+ "type": "text/html",
  "href": "https://${PAVICS_FQDN_PUBLIC}/geoserver/"
  },
  {