Bump reqwest from 0.9.20 to 0.9.21 (#6221)

Bumps [reqwest](https://github.com/seanmonstar/reqwest) from 0.9.20 to 0.9.21.
- [Release notes](https://github.com/seanmonstar/reqwest/releases)
- [Changelog](https://github.com/seanmonstar/reqwest/blob/v0.9.21/CHANGELOG.md)
- [Commits](https://github.com/seanmonstar/reqwest/compare/v0.9.20...v0.9.21)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

programs/btc_spv_bin/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 
 [dependencies]
 clap="2.33.0"
-reqwest = { version = "0.9.20", default-features = false, features = ["rustls-tls"] }
+reqwest = { version = "0.9.21", default-features = false, features = ["rustls-tls"] }
 serde="1.0.101"
 serde_derive="1.0.101"
 serde_json = "1.0.40"