fix(node_git): always use unix path style

[trim21]

the TestGitNode_sshWithDir failed on windows because it use windows path seprator on windows. we should use path.Join to always force a path seprator.

--- FAIL: TestGitNode_sshWithDir (0.00s)
    node_git_test.go:46:
                Error Trace:    C:/Users/Trim21/proj/task/taskfile/node_git_test.go:46
                Error:          Not equal:
                                expected: "ssh://git@github.com/foo/bar.git//directory/common.yml?ref=main"
                                actual  : "ssh://git@github.com/foo/bar.git//directory\\common.yml?ref=main"

                                Diff:
                                --- Expected
                                +++ Actual
                                @@ -1 +1 @@
                                -ssh://git@github.com/foo/bar.git//directory/common.yml?ref=main
                                +ssh://git@github.com/foo/bar.git//directory\common.yml?ref=main
                Test:           TestGitNode_sshWithDir
--- FAIL: TestGitNode_httpsWithDir (0.00s)
    node_git_test.go:74:
                Error Trace:    C:/Users/Trim21/proj/task/taskfile/node_git_test.go:74
                Error:          Not equal:
                                expected: "https://github.com/foo/bar.git//directory/common.yml?ref=main"
                                actual  : "https://github.com/foo/bar.git//directory\\common.yml?ref=main"

                                Diff:
                                --- Expected
                                +++ Actual
                                @@ -1 +1 @@
                                -https://github.com/foo/bar.git//directory/common.yml?ref=main
                                +https://github.com/foo/bar.git//directory\common.yml?ref=main
                Test:           TestGitNode_httpsWithDir
FAIL