bug #152 Make ApiTestCase::tearDown protected (emodric)

This PR was merged into the 5.0-dev branch.

Discussion
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| Q               | A
| --------------- | ---
| Bug fix?        | yes?
| New feature?    | no
| BC breaks?      | no
| Related tickets | N/A
| License         | MIT

PHPUnit `TestCase::tearDown` is protected itself, so makes sense for this one to be too.

Commits
-------

6a1a432 Make ApiTestCase::tearDown protected

src/ApiTestCase.php

@@ -117,7 +117,7 @@ public function setUpDatabase()
         }
     }
 
-    public function tearDown(): void
+    protected function tearDown(): void
     {
         if (null !== $this->client &&
             null !== $this->client->getContainer() &&