state msrv

Following is 1.53 output

    Compiling clap_derive v3.0.0
  error[E0658]: arbitrary expressions in key-value attributes are unstable
    --> /home/tshepang/.cargo/registry/src/github.com-1ecc6299db9ec823/clap_derive-3.0.0/src/lib.rs:16:10
     |
  16 | #![doc = include_str!("../README.md")]
     |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |
     = note: see issue #78835 <rust-lang/rust#78835> for more information

Cargo.toml

@@ -3,6 +3,7 @@ name = "post"
 version = "0.0.0"
 authors = ["Tshepang Lekhonkhobe <tshepang@gmail.com>"]
 edition = "2018"
+rust-version = "1.54"
 
 [dependencies]
 anyhow = "1"