ci(base-images): also trigger rebuild on .docker/install-base-deps.sh changes

base-images.yml's master-push trigger had a path filter listing only
backend/Dockerfile.base-grpc-builder and .github/workflows/base-images.yml.
That misses .docker/install-base-deps.sh — which is the actual source
of truth for what goes into each base image (apt deps, gRPC, conditional
CUDA/ROCm/Vulkan installs). The script is bind-mounted into the base
Dockerfile at build time; changes to it would change the produced
images, but without this path filter, the workflow wouldn't auto-rebuild
on those changes. Stale bases would persist until Saturday's cron or a
manual workflow_dispatch.

Same applies to .docker/apt-mirror.sh, also bind-mounted by the base
Dockerfile.

Add both to the trigger paths so consumer-affecting changes to either
file rebuild the bases automatically.

Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>