feat: add Python dependency parsing with extras support

packagemanager/errors.go

@@ -0,0 +1,15 @@
+package packagemanager
+
+import (
+	"errors"
+)
+
+var (
+	ErrPackageNotFound      = errors.New("package not found")
+	ErrFailedToFetchPackage = errors.New("failed to fetch package")
+	ErrFailedToParsePackage = errors.New("failed to parse package")
+	ErrNoPackagesFound      = errors.New("no packages found")
+	ErrAuthorNotFound       = errors.New("author not found")
+
+	ErrGitHubRateLimitExceeded = errors.New("github api rate limit exceeded")
+)