feat(vault-namespace): set 'X-Vault-Namespace' when a client has it

[kakoc]

related issue #123

[codecov]

Codecov Report

Merging #137 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #137   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         2           
  Lines          143       146    +3     
  Branches        35        37    +2     
=========================================
+ Hits           143       146    +3     

Impacted Files	Coverage Δ
src/index.js	100.00% <100.00%> (ø)

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[Pluies]

Hi @kr1sp1n 👋
Would it be possible to look into merging this feature? I understand that it's a very specific Entreprise-only (AFAIK) Vault feature, but having support would be hugely useful for us as well.
Thank you!

• Florent

[Pluies]

FWIW I've forked node-vault, applied @kakoc 's patch and published the package under a personal NPM repo (@florentdelannoyynap/node-vault) and I can report everything is working beautifully!

[ChamNouki]

If i well understand how this package work, following code should do the same thing than this PR :

const vaultOptions: VaultOptions = {
  requestOptions: {
    headers: {
      'X-Vault-Namespace': process.env.VAULT_NAMESPACE
    }
  }
};

const vault = Vault(vaultOptions);

However I still have an error but this time it's a 404.

[kr1sp1n]

@kakoc Thanks for your PR 👍
@Pluies Released as v0.9.18 🎉
Closes #123