pip: bump edk2-pytool-library from 0.21.5 to 0.21.8

Bumps [edk2-pytool-library](https://github.com/tianocore/edk2-pytool-library) from 0.21.5 to 0.21.8.
- [Release notes](https://github.com/tianocore/edk2-pytool-library/releases)
- [Commits](https://github.com/tianocore/edk2-pytool-library/compare/v0.21.5...v0.21.8)

---
updated-dependencies:
- dependency-name: edk2-pytool-library
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pip-requirements.txt b/pip-requirements.txt
index 7cee905..e07b9ca 100644
--- a/pip-requirements.txt
+++ b/pip-requirements.txt
@@ -12,7 +12,7 @@
 # https://www.python.org/dev/peps/pep-0440/#version-specifiers

 ##

 

-edk2-pytool-library==0.21.5

+edk2-pytool-library==0.21.8

 edk2-pytool-extensions==0.27.6

 edk2-basetools==0.1.51

 antlr4-python3-runtime==4.7.1