Allow uppercase ASCII alphabet in PyPI package names (#21095) (#21217)

Backport of #21095

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

routers/api/packages/pypi/pypi.go

@@ -24,7 +24,7 @@ import (
 
 // https://www.python.org/dev/peps/pep-0503/#normalized-names
 var normalizer = strings.NewReplacer(".", "-", "_", "-")
-var nameMatcher = regexp.MustCompile(`\A[a-z0-9\.\-_]+\z`)
+var nameMatcher = regexp.MustCompile(`\A[a-zA-Z0-9\.\-_]+\z`)
 
 // https://www.python.org/dev/peps/pep-0440/#appendix-b-parsing-version-strings-with-regular-expressions
 var versionMatcher = regexp.MustCompile(`^([1-9][0-9]*!)?(0|[1-9][0-9]*)(\.(0|[1-9][0-9]*))*((a|b|rc)(0|[1-9][0-9]*))?(\.post(0|[1-9][0-9]*))?(\.dev(0|[1-9][0-9]*))?$`)