docs: Update the readme MSRV to the actual number (#1331)

Add CI job to make sure it stays up to date

Author: caspermeijn

.github/workflows/ci.yml

@@ -226,5 +226,6 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - name: Verify that Prost version is up to date in README
-        working-directory: prost
         run: grep -q "$(sed '/^version = /!d' Cargo.toml | head -n1)" README.md
+      - name: Verify that MSRV version is up to date in README
+        run: grep -q "supports $(sed -n 's/rust-version = "\(.*\)"/\1/p' Cargo.toml)\." README.md

README.md

@@ -46,7 +46,7 @@ See the [snazzy repository][snazzy] for a simple start-to-finish example.
 
 ### MSRV
 
-`prost` follows the `tokio-rs` project's MSRV model and supports 1.70. For more
+`prost` follows the `tokio-rs` project's MSRV model and supports 1.71.1. For more
 information on the tokio msrv policy you can check it out [here][tokio msrv]
 
 [tokio msrv]: https://github.com/tokio-rs/tokio/#supported-rust-versions