[11.9] Correct upload avatar endpoint (#750)

Author: GrahamCampbell

src/Api/Projects.php

@@ -1207,7 +1207,7 @@ public function uploadFile($project_id, string $file)
      */
     public function uploadAvatar($project_id, string $file)
     {
-        return $this->put($this->getProjectPath($project_id, ''), [], [], ['avatar' => $file]);
+        return $this->put('projects/'.self::encodePath($project_id), [], [], ['avatar' => $file]);
     }
 
     /**

tests/Api/ProjectsTest.php

@@ -2780,7 +2780,7 @@ public function shouldUploadAvatar(): void
         $api = $this->getApiMock();
         $api->expects($this->once())
             ->method('put')
-            ->with('projects/1/', [], [], ['avatar' => $fileName])
+            ->with('projects/1', [], [], ['avatar' => $fileName])
             ->will($this->returnValue($expectedArray));
         $this->assertEquals($expectedArray, $api->uploadAvatar(1, $fileName));
         \unlink($fileName);