Add qemu-img as dependency
    
    Otherwise we'll face failures as:
    ```
    Creating kata appliance initrd and filesystem image...
    Building failed. See log for details: /tmp/kata-rpm-post-KWiYla.log
    warning: %post(kata-osbuilder-1.10.0-7.fc33.x86_64) scriptlet failed, exit status 1
    
    Error in POSTIN scriptlet in rpm package kata-osbuilder
      Running scriptlet: kata-osbuilder-1.10.0-7.fc33.x86_64
    ```
    
    And in the log we can see:
    ```
    + Copying agent directory tree into place
    Calling osbuilder rootfs.sh on extracted rootfs
    INFO: Create symlink to /tmp in /var to create private temporal directories with systemd
    INFO: Install tmp.mount in ./etc/systemd/system
    cp: cannot stat './usr/share/systemd/tmp.mount': No such file or directory
    INFO: Create /tmp/kata-dracut-rootfs-HQchWH/etc
    INFO: Configure chrony file /tmp/kata-dracut-rootfs-HQchWH/etc/chrony.conf
    [OK] cp /usr/libexec/kata-containers/osbuilder/agent/usr/bin/kata-agent /tmp/kata-dracut-rootfs-HQchWH/usr/bin/kata-agent
    [OK] Agent installed
    INFO: Check init is installed
    [OK] init is installed
    INFO: Create /etc/resolv.conf file in rootfs if not exist
    INFO: Creating summary file
    INFO: Created summary file '/var/lib/osbuilder/osbuilder.yaml' inside rootfs
    + Calling osbuilder initrd_builder.sh
    [OK] init is installed
    [OK] Agent is installed
    INFO: Creating /tmp/kata-dracut-images-vSuihH/kata-containers-initrd.img based on rootfs at /tmp/kata-dracut-rootfs-HQchWH
    129010 blocks
    + Calling osbuilder image_builder.sh
    [OK] init is installed
    [OK] init is systemd
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop0p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop1p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop2p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop3p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop4p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop5p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop6p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop7p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop8p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop9p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop10p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop11p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop12p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop13p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop14p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop15p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop16p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop17p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop18p1 is not a block device
    losetup: /tmp/tmp.2oChG1dBux: Warning: file is smaller than 512 bytes; the loop device may be useless or invisible for system tools.
    ERROR: File /dev/loop19p1 is not a block device
    ERROR: Could not calculate the required disk size
    INFO: Creating raw disk with size 126M
    ./image-builder/image_builder.sh: line 344: qemu-img: command not found
    
    ```
    
    Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>