buildman: Add python3-pycryptodome

This is used by some Binman entry types, so add it to allow more tests
to pass.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/tools/buildman/requirements.txt b/tools/buildman/requirements.txt
index 564e548..052d0ed 100644
--- a/tools/buildman/requirements.txt
+++ b/tools/buildman/requirements.txt
@@ -1,4 +1,5 @@
 coverage==6.2
 jsonschema==4.17.3
+pycryptodome==3.20
 pyyaml==6.0
 yamllint==1.26.3