enhance: allow key override and update deps

[ecrupper]

This change allows for the following pipeline

steps:
  - name: secrets
    image: target/secret-vault:latest
    secrets: [ vault_token ]
    parameters:
      log_level: trace
      auth_method: token
      items:
        - source: secret/vela/path/hello
          path: newPath
          keys:
            message: code

  - name: view message
    image: hub.docker.target.com/alpine:latest
    commands:
      - cat /vela/secrets/newPath/code # will print secret

Also went ahead and knocked out some deps

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.60%. Comparing base (11e7d3a) to head (a1a2c7c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #458      +/-   ##
==========================================
+ Coverage   44.07%   44.60%   +0.52%     
==========================================
  Files           7        7              
  Lines         211      213       +2     
==========================================
+ Hits           93       95       +2     
  Misses        103      103              
  Partials       15       15              

Files	Coverage Δ
cmd/secret-vault/read.go	92.00% <100.00%> (+0.33%)	⬆️

[KellyMerrick]

lgtm