[BC Break] Make data providers for abstract test cases static

Author: OskarStark

Tests/ZulipTransportFactoryTest.php

@@ -25,31 +25,31 @@ public function createFactory(): TransportFactoryInterface
         return new ZulipTransportFactory();
     }
 
-    public function createProvider(): iterable
+    public static function createProvider(): iterable
     {
         yield [
             'zulip://host.test?channel=testChannel',
             'zulip://email:token@host.test?channel=testChannel',
         ];
     }
 
-    public function supportsProvider(): iterable
+    public static function supportsProvider(): iterable
     {
         yield [true, 'zulip://host?channel=testChannel'];
         yield [false, 'somethingElse://host?channel=testChannel'];
     }
 
-    public function incompleteDsnProvider(): iterable
+    public static function incompleteDsnProvider(): iterable
     {
         yield 'missing email or token' => ['zulip://testOneOfEmailOrToken@host.test?channel=testChannel'];
     }
 
-    public function missingRequiredOptionProvider(): iterable
+    public static function missingRequiredOptionProvider(): iterable
     {
         yield 'missing option: channel' => ['zulip://email:token@host'];
     }
 
-    public function unsupportedSchemeProvider(): iterable
+    public static function unsupportedSchemeProvider(): iterable
     {
         yield ['somethingElse://email:token@host?channel=testChannel'];
         yield ['somethingElse://email:token@host']; // missing "channel" option