make Package.Path() return platform independent package full path (#151)

* add .gitattributes for clean checkout on Windows

* fix Package.Path()

* update README

* update typo

Author: yimoucao

.gitattributes

@@ -0,0 +1,11 @@
+# Set default behavior to automatically normalize line endings.
+* text=auto
+
+# Force batch scripts to always use CRLF line endings so that if a repo is accessed
+# in Windows via a file share from Linux, the scripts will work.
+*.{cmd,[cC][mM][dD]} text eol=crlf
+*.{bat,[bB][aA][tT]} text eol=crlf
+
+# Force bash scripts to always use LF line endings so that if a repo is accessed
+# in Unix via a file share from Windows, the scripts will work.
+*.sh text eol=lf

README.md

@@ -122,7 +122,7 @@ run:
 
 Let's show a few, real, sometimes novel examples showcasing `bingo` capabilities:
 
-1. [`golangci-lint`](https://github.com/golangci/golangci-lint) is all-in-one lint framework. It's important to pin it on CI so CI runs are reproducible no matter what new linters are added, removed or changed in new release. Let's pin it to `v1.35.2` and use path recommended by https://golangci-lint.run/usage/install/#install-from-source doc: ` github.com/golangci/golangci-lint/cmd/golangci-lint` (funny enough they discourage `go get` exactly because of the lack of pinning features `bingo` have!)
+1. [`golangci-lint`](https://github.com/golangci/golangci-lint) is all-in-one lint framework. It's important to pin it on CI so CI runs are reproducible no matter what new linters are added, removed or changed in new release. Let's pin it to `v1.35.2` and use path recommended by https://golangci-lint.run/welcome/install/#install-from-source doc: ` github.com/golangci/golangci-lint/cmd/golangci-lint` (funny enough they discourage `go get` exactly because of the lack of pinning features `bingo` have!)
 
    ```shell
    bingo get github.com/golangci/golangci-lint/cmd/golangci-lint@v1.35.2

pkg/bingo/mod.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"log"
 	"os"
+	"path"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -70,9 +71,10 @@ func (m Package) String() string {
 	return m.Path() + "@" + m.Module.Version
 }
 
-// Path returns a full package path.
+// Path returns a full package path. package path is platform independent, usually in
+// the form of "a/b/c" with forward slashes
 func (m Package) Path() string {
-	return filepath.Join(m.Module.Path, m.RelPath)
+	return path.Join(m.Module.Path, m.RelPath)
 }
 
 // ModFile is a wrapper over module file with bingo specific data.