tonic-build can no longer build code with rust < 1.77.0, due to newer build-script syntax

[DAdolfsson]

Bug Report

Version

0.12.2

Platform

x86_64 GNU/Linux

Crates

tonic-build

Description

Since the following merge (i think)
#1821

Rust 1.75 (which I am using) can no longer build,

The issue I get is:

cargo::rerun-if-changed=proto/pts_hardware.proto`
Found a `cargo::key=value` build directive which is reserved for future use.
Either change the directive to `cargo:key=value` syntax (note the single `:`) or upgrade your version of Rust.
See https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script for more information about build script outputs.
warning: build failed, waiting for other jobs to finish...

I believe the double :: was introduced in Cargo 1.77, if this is the case this change should be reverted or MSRV should be bumped?

https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script

Best Regards
Daniel

[tottoto]

Thanks for the reporting! This seems not to be caught with testing with Rust 1.70.