react-rust-postgres: "Rocket (core) requires a more recent version of rustc."

[AkihiroSuda]

The react-rust-postgres example does not work due to "Rocket (core) requires a more recent version of rustc." error

$ docker logs react-rust-postgres_backend_1 
...
error: failed to run custom build command for `rocket v0.4.10`

Caused by:
  process didn't exit successfully: `/code/target/debug/build/rocket-918081dca64af494/build-script-build` (exit code: 101)
  --- stderr
  Error: Rocket (core) requires a more recent version of rustc.
  Installed version: 1.51.0 (2020-12-29)
  Minimum required:  1.54.0-nightly (2021-05-18)
  thread 'main' panicked at 'Aborting compilation due to incompatible compiler.', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/rocket-0.4.10/build.rs:34:13
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: build failed

0ae9d4c

[glours]

@jdrouet can you take a look please?