pip: bump edk2-pytool-extensions from 0.23.8 to 0.23.9 (#221)

Bumps
[edk2-pytool-extensions](https://github.com/tianocore/edk2-pytool-extensions)
from 0.23.8 to 0.23.9.

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

pip-requirements.txt

@@ -13,7 +13,7 @@
 ##
 
 edk2-pytool-library==0.15.3
-edk2-pytool-extensions==0.23.8
+edk2-pytool-extensions==0.23.9
 edk2-basetools==0.1.49
 antlr4-python3-runtime==4.13.0
 xmlschema==2.3.1