Merge rust-bitcoin#1723: bitcoin: Fix path to the readme

998b204 bitcoin: Fix path to the readme (Tobin C. Harding)

Pull request description:

  We moved to a submodule and didn't fix the readme path in the `bitcoin` manifest.

ACKs for top commit:
  sanket1729:
    utACK 998b204
  apoelstra:
    utACK 998b204

Tree-SHA512: c7591e05974173eddbabfa7ee0273ad4c71b103108f09e7536696593f3e181f80ecfe05a2fa312963069d35137784ccae1fbb167cceccdacb8a2fab211123bf4

Author: apoelstra

bitcoin/Cargo.toml

@@ -8,7 +8,7 @@ documentation = "https://docs.rs/bitcoin/"
 description = "General purpose library for using and interoperating with Bitcoin."
 categories = ["cryptography::cryptocurrencies"]
 keywords = [ "crypto", "bitcoin" ]
-readme = "README.md"
+readme = "../README.md"
 edition = "2018"
 exclude = ["tests", "contrib"]