Fix typos in benchmark_config file

frameworks/Python/API-Hour/benchmark_config

@@ -22,7 +22,7 @@
       "database_os": "Linux",
       "display_name": "API-Hour+aiohttp.web+pgsql",
       "notes": "Python 3 + AsyncIO + aiohttp.web + PostgreSQL"
-    }
+    },
     "redis": {
       "setup_file": "setup",
       "db_url": "/db_redis",
@@ -42,7 +42,7 @@
       "database_os": "Linux",
       "display_name": "API-Hour+aiohttp.web+redis",
       "notes": "Python 3 + AsyncIO + aiohttp.web + Redis"
-    }
+    },
     "json": {
       "setup_file": "setup",
       "json_url": "/json",
@@ -59,7 +59,7 @@
       "database_os": "None",
       "display_name": "API-Hour+AsyncIO",
       "notes": "Python 3 + AsyncIO"
-    }
+    },
     "plaintext": {
       "setup_file": "setup",
       "json_url": "/plaintext",