Upgrade bitflags to v2.0

This updates our direct bitflags dependency from 1.3.2 to 2.0. There
are no obvious changes necessary to our code base according to the
release notes [1].

Unfortunately for dev builds we now have 2 bitflags versions as clap
still depends on the 1.3.2 version. To resolve this issue there is an
extra PR open [2].

[1] https://github.com/bitflags/bitflags/releases
[2] serialport#76

Signed-off-by: Richard Leitner <[email protected]>

Cargo.toml

@@ -15,7 +15,7 @@ keywords = ["serial", "hardware", "system", "RS232"]
 categories = ["hardware-support"]
 
 [target."cfg(unix)".dependencies]
-bitflags = "1.3.2"
+bitflags = "2.0"
 cfg-if = "1.0.0"
 nix = { version = "0.26", default-features = false, features = ["fs", "ioctl", "poll", "signal", "term"] }