v3.12.0

## Features

- Upgrade Alpine to 3.13
- Set a 10s ping with a 60s exit ping for all openvpn configurations, so that openvpn exits and restarts if it does not receive a ping for 60s
- Openvpn exits if it encounters a TLS issue. It will then be restarted by the entrypoint program.
- `OPENVPN_MSSFIX` environment variable
- Upgrade Openvpn to 2.5.0

### Servers

- Update Nordvpn hardcoded servers list

## Bug fixes

- Openvpn restart loop because of `ping-restart` options, now replaced by `ping-exit`.

## Documentation

- Most documentation moved to the Wiki (reached the Docker hub readme limit of 25KB)

## Maintenance

- Configure dependabot to monitor go modules and docker dependencies
- Update and improve development container configuration
- Update golibs and its params package
- OpenVPN BuildConf arity reduced
- Unit test internal/provider/utils.go
- Update golangci-lint to v1.35.2

### CI

- All build workflows merged into a single yml configuration file
- Go mod tidy check
- Remove duplicate COPY in Dockerfile
- Fix xcputranslate version and uage
- Set default `BUILDPLATFORM=linux/amd64` in Dockerfile for older Docker CLIs