xk6-dashboard `v0.7.6` is here 🎉!

This is a maintenance release, changes:

- Updated k6 to v1.0.0
- Use shared GitHub workflows from xk6
- Updated tooling dependencies
  - `go`: 1.24
  - `golangci-lint`: 2.1.6
  - `xk6`: 0.19.2
  - `gosec`: 2.22.4
  - `govulncheck`: 1.1.4
  - `goreleaser`: 2.9.0
- Added support for [Development Containers](https://containers.dev/)
- Generate Makefile from `CONTRIBUTING.md`
