Fix patchwheel.ParseWheelFilename to extract basename (#2521)

## Why
This is a minor change but makes it easier to use, no need to remember
doing this on the caller side.
Relying on this in #2520
Follow up to #2427

## Tests
New unit tests.

Author: denik

libs/patchwheel/parse.go

@@ -2,6 +2,7 @@ package patchwheel
 
 import (
 	"fmt"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -39,6 +40,7 @@ func calculateNewVersion(info WheelInfo, mtime time.Time) (newVersion, newFilena
 // The function does not try hard to validate if the format is correct, it tries to parse whatever is available.
 // However, it does require 5 or 6 components in the filename.
 func ParseWheelFilename(filename string) (WheelInfo, error) {
+	filename = filepath.Base(filename)
 	parts := strings.Split(filename, "-")
 	if len(parts) < 5 {
 		return WheelInfo{}, fmt.Errorf("invalid wheel filename format: not enough parts in %s", filename)

libs/patchwheel/parse_test.go

@@ -78,6 +78,13 @@ func TestParseWheelFilename(t *testing.T) {
 			wantTags:         []string{"py3", "none", "any"},
 			wantErr:          false,
 		},
+		{
+			filename:         "./myproj-0.1.0-py3-none-any.whl",
+			wantDistribution: "myproj",
+			wantVersion:      "0.1.0",
+			wantTags:         []string{"py3", "none", "any"},
+			wantErr:          false,
+		},
 		{
 			filename:         "myproj-0.1.0+20240303123456-py3-none-any.whl",
 			wantDistribution: "myproj",
@@ -92,6 +99,13 @@ func TestParseWheelFilename(t *testing.T) {
 			wantTags:         []string{"py3", "none", "any"},
 			wantErr:          false,
 		},
+		{
+			filename:         "subdir/myproj-0.1.0+20240303123456-py3-none-any.whl",
+			wantDistribution: "myproj",
+			wantVersion:      "0.1.0+20240303123456",
+			wantTags:         []string{"py3", "none", "any"},
+			wantErr:          false,
+		},
 		// Test cases adapted from wheelodex/wheel-filename
 		// https://github.com/wheelodex/wheel-filename/blob/f5a72b560d016cc9663c8b5a094c96dc338a2209/test/test_parse.py
 		// MIT License: https://github.com/wheelodex/wheel-filename/blob/f5a72b560d016cc9663c8b5a094c96dc338a2209/LICENSE