scraperからmainfeatureを外した

`main`で余計な依存（`getopts`）が付いていたので、外すことでビルド時間が若干早くなる。

Author: hotate29

atcoder-problems-backend/Cargo.lock

@@ -7,7 +7,7 @@ publish = false
 
 [dependencies]
 reqwest = { version = "0.11", features = ["json", "gzip"] }
-scraper = "0.12"
+scraper = { version = "0.12", default-features = false }
 chrono = "0.4"
 regex = "1"
 serde = { version = "1.0", features = ["derive"] }