go mod vendor npipe to this repo

[shueybubbles]

Fixes #117
2 parts to the fix

1. Bring the code over and verify it builds
2. Implement DialExisting to fix issue where dialing using np doesn't quit immediately when the named pipe doesn't exist.

[codecov-commenter]

Codecov Report

Merging #118 (7c4207d) into main (70e2d2b) will decrease coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #118      +/-   ##
==========================================
- Coverage   74.11%   74.06%   -0.06%     
==========================================
  Files          29       29              
  Lines        5613     5613              
==========================================
- Hits         4160     4157       -3     
- Misses       1206     1208       +2     
- Partials      247      248       +1     

see 1 file with indirect coverage changes

[shueybubbles]

I couldn't get this to work with a vendor folder whose only content was this package, nor did it work with a replace directive in go.mod. I think there's something funky with this old repo that breaks go build with new tools.

[apoorvdeshmukh]

[apoorvdeshmukh]

Do we need to create another issue to vendor this properly at some later point?

[shueybubbles]

since we keep the license and attribution intact we are ok as-is.
thx