Upgrade baibot (v1.2.0 -> v1.3.0) and adjust default static definitions prompt

The new prompt makes use of the new `baibot_conversation_start_time_utc`
prompt variable, which is not a moving target (like `baibot_now_utc`)
and as such allows prompt caching to work.

Ref: https://platform.openai.com/docs/guides/prompt-caching

roles/custom/matrix-bot-baibot/defaults/main.yml

@@ -11,7 +11,7 @@ matrix_bot_baibot_container_repo_version: "{{ 'main' if matrix_bot_baibot_versio
 matrix_bot_baibot_container_src_files_path: "{{ matrix_base_data_path }}/baibot/container-src"
 
 # renovate: datasource=docker depName=ghcr.io/etkecc/baibot
-matrix_bot_baibot_version: v1.2.0
+matrix_bot_baibot_version: v1.3.0
 matrix_bot_baibot_container_image: "{{ matrix_bot_baibot_container_image_name_prefix }}etkecc/baibot:{{ matrix_bot_baibot_version }}"
 matrix_bot_baibot_container_image_name_prefix: "{{ 'localhost/' if matrix_bot_baibot_container_image_self_build else 'ghcr.io/' }}"
 matrix_bot_baibot_container_image_force_pull: "{{ matrix_bot_baibot_container_image.endswith(':latest') }}"
@@ -155,7 +155,7 @@ matrix_bot_baibot_config_agents_static_definitions_auto: |-
   }}
 matrix_bot_baibot_config_agents_static_definitions_custom: []
 
-matrix_bot_baibot_config_agents_static_definitions_prompt: "{% raw %}You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time now is: {{ baibot_now_utc }}.{% endraw %}"
+matrix_bot_baibot_config_agents_static_definitions_prompt: "{% raw %}You are a brief, but helpful bot called {{ baibot_name }} powered by the {{ baibot_model_id }} model. The date/time of this conversation's start is: {{ baibot_conversation_start_time_utc }}.{% endraw %}"
 
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