Merge #41: Bump to version 0.4.0

a01e13d Bump to version 0.4.0 (Vladimir Fomene)

Pull request description:

ACKs for top commit:
  notmandatory:
    ACK a01e13d

Tree-SHA512: 86509b9869aca2eb5f417a22c3fc4d575ceb16259e30e6766f72820934694b0a56f78c947a636d86423cf6e7863d09ca66d4c970eac2292de3702d43a011e365

Author: vladimirfomene

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "esplora-client"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2018"
 authors = ["Alekos Filini <alekos.filini@gmail.com>"]
 license = "MIT"