fix: normalise path separators on Windows to fix sub-package tags (#165)

The git cli and the go os library return representations of the
same path using different path separators, so the comparison used here
returned false, and the absolute path of the repo was set as the
default for the pattern arg.

e.g.:
> git rev-parse --show-toplevel
C:/Users/Doug/Code/myrepo
os.getWd()
C:\\Users\\Doug\\Code\\myrepo

Using filepath.Clean() on both paths before using them normalises the
slashes to a single "\"

Author: doug-fitzmaurice-rowden

main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"path/filepath"
 	"runtime/debug"
 	"strings"
 
@@ -53,11 +54,18 @@ func defaults(flag string) string {
 
 	cwd, wdErr := os.Getwd()
 	gitRoot, grErr := git.Root()
-	if wdErr == nil && grErr == nil && cwd != gitRoot {
-		prefix := strings.TrimPrefix(cwd, gitRoot)
-		prefix = strings.TrimPrefix(prefix, string(os.PathSeparator))
-		prefix = strings.TrimSuffix(prefix, string(os.PathSeparator))
-		return path.Join(prefix, pat)
+
+	if wdErr == nil && grErr == nil {
+
+		cwd = filepath.Clean(cwd)
+		gitRoot = filepath.Clean(gitRoot)
+
+		if cwd != gitRoot {
+			prefix := strings.TrimPrefix(cwd, gitRoot)
+			prefix = strings.TrimPrefix(prefix, string(os.PathSeparator))
+			prefix = strings.TrimSuffix(prefix, string(os.PathSeparator))
+			return path.Join(prefix, pat)
+		}
 	}
 
 	return def