Release 0.7.1: Deprecate more thoroughly

• Restore stub of assertify_proc_macros sub-crate so that I can mark it deprecated and publish it.
• Mark both crates with a deprecated badge in Cargo.toml as instructed by lib.rs’s maintainer page.
• Make sure deprecation notice shows up clearly on docs.rs.

0.7.0: Deprecate in favor of assert2

Changes

• Decided to deprecate. The assert2 crate’s macros are strictly better than this crate’s assertify!, and the testify! macro is easy to replace.
• Consolidated old assertify_proc_macros crate into this crate. This crate only defines the procedural macros and does not actually use them, so there is no need for a sub-crate.
• Removed use of proc_macro_hack, which hasn’t been needed since Rust 1.45 (released in July 2020).
• Added change log.