Updates addon to remove the deprecations in 2.1

Author: chris-79

TaxonomyFilterFilter.php

@@ -3,7 +3,7 @@
 namespace Statamic\Addons\TaxonomyFilter;
 
 use Statamic\Extend\Filter;
-use Statamic\API\TaxonomyTerm;
+use Statamic\API\Term;
 use Statamic\API\Helper;
 
 class TaxonomyFilterFilter extends Filter
@@ -21,7 +21,7 @@ public function filter()
       $tf_group = $this->get('tf_group');
       $tf_slug = $this->get('tf_slug',$this->context['last_segment']);
 
-      $taxonomy_object = TaxonomyTerm::getFromTaxonomy($tf_group,$tf_slug);
+      $taxonomy_object = Term::whereSlug($tf_slug,$tf_group);
       $the_id = $taxonomy_object->get('id');
       $tf_group_array = Helper::ensureArray($entry->get($tf_group));