Assure compatibility with Vault >= 1.13

[arnecls]

These are the changes mentioned in #134.

The following dependencies have been updated:

• github.com/hashicorp/go-hclog v1.6.2 -> v1.6.3
• github.com/hashicorp/vault/api v1.12.1 -> v1.14.0
• github.com/prometheus/client_golang v1.19.0 -> v1.19.1
• github.com/prometheus/common v0.50.0 -> v0.53.0

This version has been tested with a custom build on vault 1.13.11.
The binary used for testing this change is available through a release on the fork: https://github.com/arnecls/vault-plugin-secrets-github/releases/tag/v2.1.1

Additional changes

• CG_ENABLED=0 set during build
• A plugin version is now passed properly to vault (shows during vault plugin list)
• The module name has been changed to just vault-plugin-secrets-github. This makes fork handling simpler as otherwise submodule from main, and not the fork, would be used
• Adjusted several metadata values because of the module name change
• Removed module proxying. It's not needed anymore (as far as I can see)

Note

This change might be incompatible with vault 1.12 or earlier.
This has not been tested yet.