cargo: Relax required version for pest crate

Instead of requiring version '2.6', require version '2'

Signed-off-by: Anderson Toshiyuki Sasaki <[email protected]>

Author: ansasaki

Cargo.toml

@@ -27,8 +27,8 @@ keylime = { version = "=0.2.4", path = "keylime" }
 libc = "0.2.43"
 log = "0.4"
 openssl = "0.10.15"
-pest = "2.6"
-pest_derive = "2.6"
+pest = "2"
+pest_derive = "2"
 picky-asn1-der = "0.4"
 picky-asn1-x509 = "0.12"
 pretty_env_logger = "0.4"