Update bitflags requirement from 1.2 to 2.1 in /lib/kpi

Updates the requirements on [bitflags](https://github.com/bitflags/bitflags) to permit the latest version.
- [Release notes](https://github.com/bitflags/bitflags/releases)
- [Changelog](https://github.com/bitflags/bitflags/blob/main/CHANGELOG.md)
- [Commits](bitflags/bitflags@1.2.0...2.1.0)

---
updated-dependencies:
- dependency-name: bitflags
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

lib/kpi/Cargo.toml

@@ -8,7 +8,7 @@ license = "MIT OR Apache-2.0"
 [dependencies]
 x86 = { version = "0.52", features = ["unstable"] }
 abomonation = { git="https://github.com/hunhoffe/abomonation.git", branch="no-std", default-features = false }
-bitflags = "1.2"
+bitflags = "2.1"
 core2 = { version = "0.3", default-features = false, features = [ "alloc" ] }
 serde = { version = "1.0", default-features = false, features = ["derive", "alloc"] }
 serde_cbor = { version = "0.11", default-features = false, features = ["alloc"] }