Set cargo.toml version to default value, add comment

Author: blahgeek

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "emacs-lsp-booster"
-version = "0.1.0"
+version = "0.0.0"  # this package will never be published as lib, so ignore this version field
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html