Change Event Espresso Custom post type Archive titles by using the `get_the_archive_title` filter hook

ee_get_the_archive_title.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

function my_theme_ee_archive_titles( $title ) {
    if ( is_post_type_archive('espresso_events') ) {
        $title = 'Upcoming Events';
    } elseif ( is_post_type_archive('espresso_venues') ) {
        $title = 'Locations';
    } elseif ( is_post_type_archive('espresso_people') ) {
        $title = 'Staff';
    }
    return $title;
}
add_filter( 'get_the_archive_title', 'my_theme_ee_archive_titles' );