Tonic build is not working in Rust Workspace project

[CrazyRoka]

When compiling the project I receive this error message:

warning: /home/roka/Project/problems-service/Cargo.toml: unused manifest key: build
   Compiling problems-service v0.1.0 (/home/roka/Project/problems-service)
   Compiling httparse v1.3.4
   Compiling want v0.3.0
   Compiling iovec v0.1.4
error[E0433]: failed to resolve: use of undeclared type or module `tonic_build`
 --> problems-service/build.rs:2:5
  |
2 |     tonic_build::compile_protos("proto/problems.proto").unwrap();
  |     ^^^^^^^^^^^ use of undeclared type or module `tonic_build`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0433`.
error: could not compile `problems-service`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

Project tree

├── Cargo.lock
├── Cargo.toml
└── problems-service
    ├── build.rs
    ├── Cargo.toml
    ├── proto
    │   └── problems.proto
    └── src
        └── main.rs

Outer cargo toml:

[workspace]

members = [
    "problems-service"
]

Inner cargo toml:

[package]
name = "problems-service"
version = "0.1.0"
authors = ["CrazyRoka <rokarostuk@gmail.com>"]
edition = "2018"

[dependencies]
prost = "0.6.1"
tonic = { version = "0.3.1", features = ["tls"] }
tokio = { version = "0.3.1", features = ["stream", "macros"] }
futures = "0.3"

[build.dependencies]
tonic-build = "0.3.1"

build.rs

fn main() {
    tonic_build::compile_protos("proto/problems.proto").unwrap();
}

Platform:
Linux roka-pc 5.4.0-52-generic #57-Ubuntu SMP Thu Oct 15 10:57:00 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Default host: x86_64-unknown-linux-gnu
stable-x86_64-unknown-linux-gnu (default)
rustc 1.47.0 (18bf6b4f0 2020-10-07)

[CrazyRoka]

Issue with [build-dependencies], my bad