Fix zipp security alert (#6383)

* Fix zipp security alert

* Remove spurious requirements.txt

Author: matteius

Pipfile

@@ -10,7 +10,6 @@ sphinx-click = "==4.*"
 sphinxcontrib-spelling = "==7.*"
 click = "==8.0.3"
 stdeb = {version="*", sys_platform = "== 'linux'"}
-zipp = {version = "==3.6.0", markers = "python_version < '3.10'"}
 pre-commit = "==2.*"
 atomicwrites = {version = "*", sys_platform = "== 'win32'"}
 pytest-cov = "==4.*"
@@ -29,6 +28,7 @@ build = "*"
 twine = "*"
 semver = "*"
 pypiserver = "2.3.2"
+zipp = "==3.21.0"
 
 [packages]
 pytz = "*"