Extract `mb-saces/rust-synapse-tools` version into a variable (`matrix_synapse_rust_synapse_compress_state_docker_image_version`) and annotate for Renovate

roles/custom/matrix-synapse/defaults/main.yml

@@ -1602,7 +1602,9 @@ matrix_synapse_forgotten_room_retention_period: 28d
 matrix_synapse_user_ips_max_age: 28d
 
 
-matrix_synapse_rust_synapse_compress_state_docker_image: "{{ matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix }}mb-saces/rust-synapse-tools:v0.0.1"
+matrix_synapse_rust_synapse_compress_state_docker_image: "{{ matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix }}mb-saces/rust-synapse-tools:{{ matrix_synapse_rust_synapse_compress_state_docker_image_version }}"
+# renovate: datasource=docker depName=registry.gitlab.com/mb-saces/rust-synapse-tools
+matrix_synapse_rust_synapse_compress_state_docker_image_version: v0.0.1
 matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix: "{{ matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix_upstream }}"
 matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix_upstream: "{{ matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix_upstream_default }}"
 matrix_synapse_rust_synapse_compress_state_docker_image_registry_prefix_upstream_default: "registry.gitlab.com/"