Bump log from 0.4.6 to 0.4.7 (#5144)

Bumps [log](https://github.com/rust-lang/log) from 0.4.6 to 0.4.7.
- [Release notes](https://github.com/rust-lang/log/releases)
- [Changelog](https://github.com/rust-lang-nursery/log/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/log/compare/0.4.6...0.4.7)

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

vote-signer/Cargo.toml

@@ -14,7 +14,7 @@ clap = "2.33"
 jsonrpc-core = "12.0.0"
 jsonrpc-derive = "12.0.0"
 jsonrpc-http-server = "12.0.0"
-log = "0.4.2"
+log = "0.4.7"
 serde = "1.0.94"
 serde_json = "1.0.40"
 solana-metrics = { path = "../metrics", version = "0.17.0" }