chore: add DEVELOPMENT.md and release instructions

[kilianc]

No description provided.

[github-actions]

🔗 Code Coverage Report at f782b0d

📔 Total: 100.0%
🎯 Threshold: 100%
✅ 100.0% >= 100%

Full coverage report

github.com/kilianc/pretender/internal/handlers/osfilereader.go:12:	ReadFile		100.0%
github.com/kilianc/pretender/internal/handlers/pretender.go:44:		NewPretender		100.0%
github.com/kilianc/pretender/internal/handlers/pretender.go:56:		HandleFunc		100.0%
github.com/kilianc/pretender/internal/handlers/pretender.go:89:		getNextResponse		100.0%
github.com/kilianc/pretender/internal/handlers/pretender.go:108:	LoadResponsesFile	100.0%
github.com/kilianc/pretender/pkg/pretender/server.go:20:		NewHTTPHandler		100.0%
github.com/kilianc/pretender/pkg/pretender/server.go:41:		NewServeMux		100.0%
github.com/kilianc/pretender/pkg/pretender/server.go:63:		NewServer		100.0%
total:									(statements)		100.0%

^{go-beautiful-html-coverage ↗}