Update protobuf requirement from = 2.16.2 to = 2.17.0

Updates the requirements on [protobuf](https://github.com/stepancheg/rust-protobuf) to permit the latest version.
- [Release notes](https://github.com/stepancheg/rust-protobuf/releases)
- [Changelog](https://github.com/stepancheg/rust-protobuf/blob/master/CHANGELOG.md)
- [Commits](stepancheg/rust-protobuf@v2.16.2...v2.16.2)

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

Cargo.toml

@@ -13,7 +13,7 @@ include = ["src/**/*", "Cargo.toml"]
 
 [dependencies]
 bytes = "0.5"
-protobuf = "= 2.16.2"
+protobuf = "= 2.17.0"
 byteorder = "1.3.4"
 integer-encoding = "1.1.5"
 log = "0.4.8"