fix: [#317] Update deployer runtime base image from bookworm-slim to trixie-slim

The build stage was updated to rust:trixie (GLIBC 2.39), but the runtime
stage was still using debian:bookworm-slim (GLIBC 2.36/2.37). This caused
GLIBC version mismatch errors when running the container.

Updated runtime FROM to debian:trixie-slim to ensure compiled binary
runs with compatible GLIBC version.

Author: josecelano

docker/deployer/Dockerfile

@@ -63,7 +63,7 @@ RUN mkdir -p /app/bin/ && cp /build/src/target/release/torrust-tracker-deployer
 ## =============================================================================
 ## Runtime Image
 ## =============================================================================
-FROM debian:bookworm-slim AS runtime
+FROM debian:trixie-slim AS runtime
 
 # Metadata
 LABEL org.opencontainers.image.title="Torrust Tracker Deployer"