vulkan/compile_shaders.sh: Fix ShellCheck SC2068

Author: mpiatka

src/video_display/vulkan/shaders/compile_shaders.sh

@@ -7,7 +7,7 @@ DEST_PATH=../../../../share/ultragrid/vulkan_shaders
 
 declare -a SHADERS=("render.vert" "render.frag" "RGB10A2_conv.comp" "UYVA16_conv.comp" "UYVY8_conv.comp")
 
-for shader in ${SHADERS[@]}; do
+for shader in "${SHADERS[@]}"; do
 	echo "$GLSLC $SOURCE_PATH/$shader -o $DEST_PATH/$shader.spv"
 	$GLSLC $SOURCE_PATH/$shader -o $DEST_PATH/$shader.spv
 done