git-ref-format: prepare git-ref-format crates for publishing

Attempting to publish these crates results in errors that the
`description` field is missing and that the path dependencies do not
specify versions.

Add the `description` and `keywords` fields to `git-ref-format-core`,
`git-ref-format-macro` and `git-ref-format`.

Add the versions for the dependent crates.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>

git-ref-format/core/Cargo.toml

@@ -4,6 +4,8 @@ version = "0.1.0"
 authors = ["Kim Altintop <kim@eagain.st>"]
 edition = "2018"
 license = "GPL-3.0-or-later"
+description = "Core types for the git-ref-format crate"
+keywords = ["git", "references"]
 
 [lib]
 doctest = false