Upgrade matrix-alertmanager-receiver (2025.9.10 -> 2025.9.17) and switch from `computed-values` to in-template logic

Ref:

- https://github.com/metio/matrix-alertmanager-receiver/releases/tag/2025.9.17
- https://github.com/metio/matrix-alertmanager-receiver/pull/94

roles/custom/matrix-alertmanager-receiver/defaults/main.yml

@@ -11,7 +11,7 @@
 matrix_alertmanager_receiver_enabled: true
 
 # renovate: datasource=docker depName=docker.io/metio/matrix-alertmanager-receiver
-matrix_alertmanager_receiver_version: 2025.9.10
+matrix_alertmanager_receiver_version: 2025.9.17
 
 matrix_alertmanager_receiver_scheme: https
 
@@ -159,30 +159,20 @@ matrix_alertmanager_receiver_config_templating_external_url_mapping: {}
 #   "http://prometheus:8081": https://another.prometheus.example.com
 matrix_alertmanager_receiver_config_templating_generator_url_mapping: {}
 
-# Controls the `templating.computed-values` configuration setting.
-matrix_alertmanager_receiver_config_templating_computed_values: "{{ matrix_alertmanager_receiver_config_templating_computed_values_default + matrix_alertmanager_receiver_config_templating_computed_values_auto + matrix_alertmanager_receiver_config_templating_computed_values_custom }}"
-matrix_alertmanager_receiver_config_templating_computed_values_default:
-  - values:  # always set 'color' to 'yellow'
-      color: yellow
-  - values:  # set 'color' to 'orange' when alert label 'severity' is 'warning'
-      color: orange
-    when-matching-labels:
-      severity: warning
-  - values:  # set 'color' to 'red' when alert label 'severity' is 'critical'
-      color: red
-    when-matching-labels:
-      severity: critical
-  - values:  # set 'color' to 'green' when alert status is 'resolved'
-      color: green
-    when-matching-status: resolved
-matrix_alertmanager_receiver_config_templating_computed_values_auto: []
-matrix_alertmanager_receiver_config_templating_computed_values_custom: []
-
 # Controls the `templating.firing-template` configuration setting.
 matrix_alertmanager_receiver_config_templating_firing_template: |-
   {% raw %}
+  {{ $color := "yellow" }}
+  {{ if eq .Alert.Labels.severity "warning" }}
+  {{ $color = "orange" }}
+  {{ else if eq .Alert.Labels.severity "critical" }}
+  {{ $color = "red" }}
+  {{ end }}
+  {{ if eq .Alert.status "resolved" }}
+  {{ $color = "green" }}
+  {{ end }}
   <p>
-    <strong><font color="{{ .ComputedValues.color }}">{{ .Alert.Status | ToUpper }}</font></strong>
+    <strong><font color="{{ $color }}">{{ .Alert.Status | ToUpper }}</font></strong>
     {{ if .Alert.Labels.name }}
       {{ .Alert.Labels.name }}
     {{ else if .Alert.Labels.alertname }}
@@ -211,7 +201,7 @@ matrix_alertmanager_receiver_config_templating_firing_template: |-
 # Controls the `templating.resolved-template` configuration setting.
 matrix_alertmanager_receiver_config_templating_resolved_template: |-
   {% raw %}
-  <strong><font color="{{ .ComputedValues.color }}">{{ .Alert.Status | ToUpper }}</font></strong>
+  <strong><font color="green">{{ .Alert.Status | ToUpper }}</font></strong>
   {{ if .Alert.Labels.name }}
     {{ .Alert.Labels.name }}
   {{ else if .Alert.Labels.alertname }}

roles/custom/matrix-alertmanager-receiver/tasks/validate_config.yml

@@ -24,3 +24,6 @@
   when: "lookup('ansible.builtin.varnames', ('^' + item.old + '$'), wantlist=True) | length > 0"
   with_items:
     - {'old': 'matrix_alertmanager_receiver_container_image_name_prefix', 'new': 'matrix_alertmanager_receiver_container_image_registry_prefix'}
+    - {'old': 'matrix_alertmanager_receiver_config_templating_computed_values', 'new': '<superseded by logic in the firing or resolved template; see https://github.com/metio/matrix-alertmanager-receiver/pull/94'}
+    - {'old': 'matrix_alertmanager_receiver_config_templating_computed_values_auto', 'new': '<superseded by logic in the firing or resolved template; see https://github.com/metio/matrix-alertmanager-receiver/pull/94'}
+    - {'old': 'matrix_alertmanager_receiver_config_templating_computed_values_custom', 'new': '<superseded by logic in the firing or resolved template; see https://github.com/metio/matrix-alertmanager-receiver/pull/94'}

roles/custom/matrix-alertmanager-receiver/templates/config.yaml.j2

@@ -26,10 +26,6 @@ templating:
   # value is the mapped value which will be available as '.GeneratorURL' in templates
   generator-url-mapping: {{ matrix_alertmanager_receiver_config_templating_generator_url_mapping | to_json }}
 
-  # computation of arbitrary values based on matching alert annotations, labels, or status
-  # values will be evaluated top to bottom, last entry wins
-  computed-values: {{ matrix_alertmanager_receiver_config_templating_computed_values | to_json }}
-
   # template for alerts in status 'firing'
   firing-template: {{ matrix_alertmanager_receiver_config_templating_firing_template | to_json }}