More PHP 7 fixes

composer.lock

@@ -1424,5 +1424,5 @@
     "platform-overrides": {
         "php": "7.1.33"
     },
-    "plugin-api-version": "2.2.0"
+    "plugin-api-version": "2.3.0"
 }

tests/cases/Misc/TestContext.php

@@ -25,7 +25,7 @@ class TestContext extends \JKingWeb\Arsse\Test\AbstractTest {
     public function testSetContextOptions(string $method, array $input, $output, bool $not): void {
         $parent = new Context;
         $c = ($not) ? $parent->not : $parent;
-        $default = (new \ReflectionProperty($c, $method))->getDefaultValue();
+        $default = (new \ReflectionClass($c))->getDefaultProperties()[$method];
         $this->assertFalse($c->$method(), "Context method did not initially return false");
         if (in_array($method, $this->ranges)) {
             $this->assertEquals([null, null], $c->$method, "Context property is not initially a two-member falsy array");