doc: update README to align with the new project brand (#158)

Signed-off-by: Feynman Zhou <[email protected]>
Signed-off-by: Feynman Zhou <[email protected]>
Co-authored-by: Pritesh Bandi <[email protected]>

README.md

@@ -4,4 +4,28 @@
 [![codecov](https://codecov.io/gh/notaryproject/notation-core-go/branch/main/graph/badge.svg)](https://codecov.io/gh/notaryproject/notation-core-go)
 [![Go Reference](https://pkg.go.dev/badge/github.com/notaryproject/notation-core-go.svg)](https://pkg.go.dev/github.com/notaryproject/notation-core-go@main)
 
-Contains support for Notary Project signature envelope, and format specific implementation
+notation-core-go provides core crypto functionality for notation-go and implements signature generation, parsing and revocation related functionalities based on the [Notary Project specifications](https://github.com/notaryproject/specifications). It also provides validation functionality for certificate and certificate chain.
+
+notation-core-go reached a stable release as of July 2023 and continues to be actively developed and maintained.
+
+Please visit [README](https://github.com/notaryproject/.github/blob/main/README.md) to know more about Notary Project.
+
+> [!NOTE]
+> The Notary Project documentation is available [here](https://notaryproject.dev/docs/).
+
+## Table of Contents
+- [Documentation](#documentation)
+- [Code of Conduct](#code-of-conduct)
+- [License](#license)
+
+## Documentation
+
+Library documentation is available at [Go Reference](https://pkg.go.dev/github.com/notaryproject/notation-core-go).
+
+## Code of Conduct
+
+This project has adopted the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md). See [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md) for further details.
+
+## License
+
+This project is covered under the Apache 2.0 license. You can read the license [here](LICENSE).