.gitea/workflows: add libvulkan-dev + glslang-tools to daedalus-v4l2 Debian build deps

The daedalus-v4l2 build-deb.sh (post marfrit-packages#72) now fetches
+ cmake-builds daedalus-fourier into a per-build temp prefix before
building the daemon, so the static-archive can be linked in.
daedalus-fourier's CMakeLists requires Vulkan headers and glslangValidator
(for SPIR-V compilation of the .comp compute shaders).  Without them
the configure step on the debian-aarch64 runner fails with:

  CMake Error at FindPackageHandleStandardArgs.cmake:233 (message):
    Could NOT find Vulkan (missing: Vulkan_LIBRARY Vulkan_INCLUDE_DIR)

(Observed on Gitea Actions run 1056.)

Add `libvulkan-dev` and `glslang-tools` to the apt-get install line so
the in-build daedalus-fourier compile succeeds and the daemon can link.

.gitea/workflows/build.yml

@@ -1166,9 +1166,18 @@ jobs:
           # daemon never link-binds against libav (Option γ — dlopen
           # at runtime), so any header set with the right struct
           # definitions works.
+          # libvulkan-dev + glslang-tools: needed by the in-build
+          # daedalus-fourier fetch (build-deb.sh fetches the sibling
+          # library, cmake-builds it into a temp prefix, then the
+          # daedalus daemon static-links against it via pkg-config).
+          # Without these, daedalus-fourier's find_package(Vulkan)
+          # and glslangValidator find_program both fail at configure
+          # time.  See marfrit/daedalus-fourier PR #1 +
+          # reauktion/daedalus-v4l2 PR #13.
           retry apt-get install -y --no-install-recommends \
               build-essential cmake ninja-build pkg-config git \
               libavcodec-dev libavformat-dev libavutil-dev libdrm-dev \
+              libvulkan-dev glslang-tools \
               linux-libc-dev \
               curl ca-certificates openssh-client rsync dpkg-dev