install libunwind-dev to resolve pkg conflict

.github/workflows/codeql-buildscript.sh

@@ -1,9 +1,14 @@
 #!/usr/bin/env bash
 
+# gstreamer and libc++ want different versions of libunwind-dev.
+# We explicitly install the version that gstreamer wants so
+# we don't get install errors.
+
 sudo apt-get install -y --no-install-recommends \
     git cmake pkg-config ninja-build clang clang-tools \
     libgl-dev libgles-dev libegl-dev libvulkan-dev libdrm-dev libgbm-dev libsystemd-dev libinput-dev libudev-dev libxkbcommon-dev \
-    libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
+    libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
+    libunwind-dev
 
 $WRAPPER cmake \
     -S . -B build \