Merge #110: Update rustls dependency

f5a438c Bump version to 0.16.0 (Tobin C. Harding)
9a7cc14 Update rustls dependency to version 0.21 (Tobin C. Harding)

Pull request description:

  Update the `rustls` dependency to version 0.21 and bump the version of this crate to 0.16 so the change can be released.

  I don't know what stage in your release cycle you guys are up to so I put the version bump as a separate patch - can drop it if not needed.

  Done to help with bitcoindevkit/rust-esplora-client#51

ACKs for top commit:
  danielabrozzoni:
    utACK f5a438c

Tree-SHA512: 106cbe57651a6e1365f87836598cbec9b1e837f0376ddc1c56cb75e5615543659f5c05cea7d5eb8da8b6cf278fcbe6ef866a019b9829db40cc8055798eb0f541

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "electrum-client"
-version = "0.15.1"
+version = "0.16.0"
 authors = ["Alekos Filini <[email protected]>"]
 license = "MIT"
 homepage = "https://github.com/MagicalBitcoin/rust-electrum-client"
@@ -25,7 +25,7 @@ serde_json = { version = "^1.0" }
 
 # Optional dependencies
 openssl = { version = "0.10", optional = true }
-rustls = { version = "0.20", optional = true, features = ["dangerous_configuration"] }
+rustls = { version = "0.21", optional = true, features = ["dangerous_configuration"] }
 webpki = { version = "0.22", optional = true }
 webpki-roots = { version = "0.22", optional = true }