Any hook for pre-plugin-update -either bulk or single plugin update

Here are two untested ideas:

Idea #1:

If you want to hook before an instance of the Plugin_Upgrader class is created with:

$upgrader = new Plugin_Upgrader( ... )

where the upgrades are activated with:

$upgrader->upgrade($plugin);          // for a single plugin upgrade
$upgrader->bulk_upgrade( $plugins );  // for bulk plugins upgrades

then you could try:

/**
 * Idea #1 - Prior to plugin (bulk or single) upgrades
 */

add_action( 'admin_action_upgrade-plugin', function() {
    add_action( 'check_admin_referer', 'wpse_referer', 10, 2 );
});

add_action( 'admin_action_bulk-update-plugins', function() {
    add_action( 'check_admin_referer', 'wpse_referer', 10, 2 );
});

function wpse_referer( $action, $result )
{
    remove_action( current_filter(), __FUNCTION__, 10 );

    if( $result )
    { 
        if( 'bulk-update-plugins' === $action )
        {
            // Do stuff before we run the bulk upgrade
        } 
        elseif( 'upgrade-plugin_' === substr( $action, 0, 15 )  )
        {
            // Do stuff before we run the single plugin upgrade
        }
    }
}

Idea #2:

If you want to hook deeper into the Plugin_Upgrader object, then you could try for example to hijack the upgrader_pre_install filter for the single upgrade case:

/**
 * Idea #2 - Prior to a single plugin upgrade
 */

add_action( 'admin_action_upgrade-plugin', function() {
    add_action( 'upgrader_pre_install', 'wpse_upgrader_pre_install', 99, 2 );
});

function wpse_upgrader_pre_install( $return, $plugin )
{
    if ( ! is_wp_error( $return ) ) 
    {
        // Do stuff before we run the single plugin upgrade
    }
    remove_action( current_filter(), __FUNCTION__, 99 );
    return $return;
}

Similarly you could hijack the upgrader_clear_destination filter for the bulk upgrades:

/**
 * Idea #2 - Prior to bulk plugins upgrade
 */

add_action( 'admin_action_bulk-update-plugins', function() {
    add_action( 'upgrader_clear_destination', 'wpse_upgrader_clear_destination', 99, 4 );
});

function wpse_upgrader_clear_destination( $removed, $local_destination, 
    $remote_destination, $plugin )
{
    if ( ! is_wp_error( $removed ) ) 
    {
        // Do stuff before we run the bulk plugins upgrades
    }
    remove_action( current_filter(), __FUNCTION__, 99 );
    return $removed;
}

Hopefully you can adjust this to your needs, if it works 😉