Add more helper methods to KeyValue expression

Signed-off-by: davidarendsen <davidarendsen@hey.com>

tests/Function/FilterFunctionTest.php

@@ -9,10 +9,10 @@ final class FilterFunctionTest extends TestCase {
 
     public function testSimpleFilter()
     {
-        $expression = new Filter(KeyValue::setEquals('_measurement', 'test_measurement')
-            ->andEquals('_field', 'user')
-            ->orEquals('_field', 'field2')
-            ->andEquals('user', 'my_username')
+        $expression = new Filter(KeyValue::setEqualTo('_measurement', 'test_measurement')
+            ->andEqualTo('_field', 'user')
+            ->orEqualTo('_field', 'field2')
+            ->andEqualTo('user', 'my_username')
         );
 
         $query = '|> filter(fn: (r) => r._measurement == "test_measurement" and r._field == "user" or ' .