Merge #511: Add base64 feature

2c67681 Add base64 feature (Tobin C. Harding)

Pull request description:

  Add a "base64" feature that enables the `base64` dependency in `rust-bitcoin`. This enables `Psbt::from_str()`.

  Fix: #480

ACKs for top commit:
  sanket1729:
    ACK 2c67681

Tree-SHA512: 24af82329cbbba0fff4bbb686f6108a879163dd44d7fa738677d94daf96a0a892f20f3780d4c2d6a17b183f0aa60423192340420f039d0b39bfde2422262151e

Author: sanket1729

Cargo.toml

@@ -20,6 +20,7 @@ trace = []
 unstable = []
 serde = ["actual-serde", "bitcoin/serde"]
 rand = ["bitcoin/rand"]
+base64 = ["bitcoin/base64"]
 
 [dependencies]
 bitcoin = { version = "0.29.1", default-features = false }

contrib/test.sh

@@ -2,7 +2,7 @@
 
 set -ex
 
-FEATURES="compiler serde rand"
+FEATURES="compiler serde rand base64"
 
 cargo update -p serde --precise 1.0.142
 cargo update -p serde_derive --precise 1.0.142