Version bump from tonic 0.4 to 0.6.

[comath]

The code in the repo uses tonic 0.6.2, but the version on crates.io uses 0.4.2.

My project successfully builds and passes tests with:

grpc-web-client = { git = "https://github.com/titanous/grpc-web-client" }

but fails with:

grpc-web-client = "0.1.2"

I think you just need to bump to 0.1.3 and re-release.

[devashishdxt]

I've created a crate based on this with updated dependencies: https://crates.io/crates/tonic-web-wasm-client