Bump env_logger and retry, fix test

[guerzon]

Hello,

Please accept this PR to bump the versions of the following dependencies:

• env_logger
• retry

As a result of the retry update, I have also adjusted tests/rp_common.rs.

cargo test --all-features on x86_64 (Debian forky/sid):

running 9 tests
test src/lib.rs - (line 87) ... ignored
test src/lib.rs - (line 95) ... ignored
test src/lib.rs - (line 372) - compile ... ok
test src/lib.rs - (line 280) - compile ... ok
test src/lib.rs - (line 413) - compile ... ok
test src/lib.rs - (line 134) - compile ... ok
test src/lib.rs - (line 505) - compile ... ok
test src/jwt/mod.rs - jwt::NormalizedJsonWebTokenType (line 61) ... ok
test src/client.rs - client::Client (line 33) ... ok

test result: ok. 7 passed; 0 failed; 2 ignored; 0 measured; 0 filtered out; finished in 1.65s

Thanks,
Lester