scripts/requirements: bump imgtool to 2.0.0

Resolves incorrectly located `image_ok` tag in generated hex files when
CONFIG_MCUBOOT_GENERATE_CONFIRMED_IMAGE is used.

Fixes #64098

Signed-off-by: Abram Early <abram.early@gmail.com>
(cherry picked from commit 5dec4fcab8bee81d1557fd6693c5f536e99060af)
diff --git a/scripts/requirements-extras.txt b/scripts/requirements-extras.txt
index f210f06..b18113d 100644
--- a/scripts/requirements-extras.txt
+++ b/scripts/requirements-extras.txt
@@ -19,7 +19,7 @@
 Pillow>=10.0
 
 # can be used to sign a Zephyr application binary for consumption by a bootloader
-imgtool>=1.9
+imgtool>=2.0.0
 
 # used by nanopb module to generate sources from .proto files
 grpcio-tools>=1.47.0