Add Cargo metadata (#82)

* Add Cargo `license` metadata

See documentation at <https://doc.rust-lang.org/cargo/reference/manifest.html#the-license-and-license-file-fields>.

* Add Cargo `keywords` metadata

See documentation at <https://doc.rust-lang.org/cargo/reference/manifest.html#the-keywords-field>.

* Add Cargo `categories` metadata

See documentation at <https://doc.rust-lang.org/cargo/reference/manifest.html#the-categories-field>.

* Add Cargo `readme` metadata

See documentation at <https://doc.rust-lang.org/cargo/reference/manifest.html#the-readme-field>.

Cargo.toml

@@ -5,6 +5,10 @@ version = "0.1.7"
 edition = "2021"
 repository = "https://github.com/sirwart/ripsecrets"
 homepage = "https://github.com/sirwart/ripsecrets"
+license = "MIT"
+readme = "README.md"
+keywords = ["security", "secret", "search"]
+categories = ["command-line-utilities", "text-processing"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html