message: github/workflows/rust.yml: bump MSRV toolchain
  Since `registry.redhat.io/rhel8/rust-toolset` is shipping
  `rust-1.47.0-1.module+el8.3.1+8546+07bf6eb2.x86_64` already, it
  should be safe to bump MSRV toolchain to `1.47.0`.
  Otherwise, the `zbus` crate (which we would like to use soon) is
  unable to build.
  xref:
diff: @@ -9,7 +9,7 @@ on:
  env:
  CARGO_TERM_COLOR: always
  # Minimum supported Rust version (MSRV)
  - ACTION_MSRV_TOOLCHAIN: 1.40.0
  + ACTION_MSRV_TOOLCHAIN: 1.47.0
  # Pinned toolchain for linting
  ACTION_LINTS_TOOLCHAIN: 1.49.0
  