cargo: bump arm-pl011-uart from 0.3.2 to 0.4.0 in /src/exercises/bare-metal/rtc (#2972)

Bumps arm-pl011-uart from 0.3.2 to 0.4.0.

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/exercises/bare-metal/rtc/Cargo.lock

@@ -10,7 +10,7 @@ publish = false
 aarch64-paging = { version = "0.10.0", default-features = false }
 aarch64-rt = "0.2.2"
 arm-gic = "0.7.1"
-arm-pl011-uart = "0.3.2"
+arm-pl011-uart = "0.4.0"
 bitflags = "2.10.0"
 chrono = { version = "0.4.42", default-features = false }
 log = "0.4.28"