pip-requirements.txt: Update to edk2-pytool-extensions 0.20.0

Updates edk2-pytool-extensions to pick up a major version release:

0.19.1 to 0.20.0 changes:

- .vscode/settings.json: Enable flake8 linting
- Add Pydocstyle
- Move dependabot.yml location
- Fix typos in robot files
- Pydocstyle Updates
- Plugin Loader Updates
- edk2_stuart_pr_eval: Improve robustness of path comparisons
- edk2_pr_eval.py: Build all packages on file change outside package
- Allow build wrappers

Cc: Sean Brogan <[email protected]>
Cc: Michael Kubacki <[email protected]>
Cc: Liming Gao <[email protected]>
Cc: Andrew Fish <[email protected]>
Cc: Leif Lindholm <[email protected]>
Signed-off-by: Michael Kubacki <[email protected]>
Reviewed-by: Sean Brogan <[email protected]>
Reviewed-by: Michael D Kinney <[email protected]>

pip-requirements.txt

@@ -13,6 +13,6 @@
 ##
 
 edk2-pytool-library==0.12.1
-edk2-pytool-extensions~=0.19.1
+edk2-pytool-extensions~=0.20.0
 edk2-basetools==0.1.39
 antlr4-python3-runtime==4.7.1