Refactor Vault backend to properly handle KV v1 and KV v2

Overview

This commit is NOT backwards compatible with Vault KV v2 configurations that include /data/ in the key path.

I have broadly refactored the Vault backend to improve K/V lookup for both KV v1 and KV v2. The change enables the proper use of the prefix configuration for the KV path and accommodates the differences between the KV v1 and KV v2 endpoints, specifically the use of data in the secret path. This returns the Vault backend back to pathing parity with the other backends.

Previous
in this configuration kv-v2 is the Secrets Engine path and data was necessary for the v2 endpoint.

[template]
mode = "0644"
src = "nested.conf.tmpl"
dest = "/tmp/confd-nested-test.conf"
keys = [
  "kv-v2/data/nested",
]

Current
In this configuration the kv-v2 Secrets Engine path is prefixed and data is handled by the backend when necessary.

[template]
mode = "0644"
src = "nested.conf.tmpl"
dest = "/tmp/confd-nested-test.conf"
prefix = "/kv-v2"
keys = [
  "/nested",
]

Changes

Major Changes

• Broadly refactor Vault client (#270) @abtreece

Minor Changes

• Add proper integration check for nested config (#248) @abtreece
• Upgrade Go version from 1.20 to 1.21 (#242) @abtreece
• Pin integration test container to 22.04 for now (#241) @abtreece
• Bump github.com/hashicorp/go-retryablehttp from 0.7.1 to 0.7.7 (#258) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.52.2 to 1.53.5 (#246) @dependabot
• Bump github.com/hashicorp/consul/api from 1.28.2 to 1.28.3 (#247) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.51.30 to 1.52.2 (#243) @dependabot
• Bump github.com/hashicorp/vault/api from 1.12.2 to 1.13.0 (#239) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.51.21 to 1.51.30 (#240) @dependabot
• Bump golang.org/x/net from 0.17.0 to 0.23.0 (#237) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.51.1 to 1.51.21 (#236) @dependabot
• Bump go.etcd.io/etcd/client/v3 from 3.5.12 to 3.5.13 (#234) @dependabot
• Bump github.com/hashicorp/vault/api from 1.10.0 to 1.12.2 (#231) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.49.4 to 1.51.1 (#229) @dependabot
• Bump google.golang.org/protobuf from 1.31.0 to 1.33.0 (#228) @dependabot
• Bump github.com/go-jose/go-jose/v3 from 3.0.1 to 3.0.3 (#226) @dependabot
• Bump github.com/hashicorp/consul/api from 1.27.0 to 1.28.2 (#224) @dependabot
• Bump github.com/gomodule/redigo from 1.8.9 to 1.9.2 (#223) @dependabot
• Bump go.etcd.io/etcd/client/v3 from 3.5.11 to 3.5.12 (#215) @dependabot
• Bump codecov/codecov-action from 3 to 4 (#217) @dependabot
• Bump release-drafter/release-drafter from 5 to 6 (#216) @dependabot
• Bump github.com/hashicorp/consul/api from 1.26.1 to 1.27.0 (#210) @dependabot
• Bump golang.org/x/crypto from 0.14.0 to 0.17.0 (#205) @dependabot
• Bump github.com/go-jose/go-jose/v3 from 3.0.0 to 3.0.1 (#204) @dependabot
• Bump github.com/aws/aws-sdk-go from 1.44.266 to 1.49.4 (#203) @dependabot
• Bump github.com/hashicorp/vault/api from 1.9.1 to 1.10.0 (#202) @dependabot
• Bump github/codeql-action from 2 to 3 (#201) @dependabot