[Cargo.toml] bump env_logger to v0.7.1

    Indent multiline messages by default
    Support more timestamp precision
    Update to the 2018 edition

[Cargo.toml] bump env_logger to v0.7.1

Author: chrissimpkins

Cargo.toml

@@ -14,7 +14,7 @@ edition = "2018"
 [dependencies]
 dialoguer = "0.5.0"
 dirs = "2.0"
-env_logger = "0.6.0"
+env_logger = "0.7.1"
 failure = "0.1"
 flate2 = "1.0.1"
 git2 = "0.8"