Print trailing newline after version

[maximiliankolb]

Without the trailing newline, the shell prompt ends up on the same line as the version.

Error: user@localhost:~# basilk --version 0.2.0user@localhost:~#

Expected output: user@localhost:~# basilk --version 0.2.0 user@localhost:~#

See https://doc.rust-lang.org/std/macro.print.html#

test

$ cargo build --release
   ...
   Compiling basilk v0.2.0 (/home/user/basilk)
    Finished `release` profile [optimized] target(s) in 31.93s

$ ./target/release/basilk --version
0.2.0