Add API doc link

Also fix headings - Markdown allows only one H1-level heading

Signed-off-by: Arthit Suriyawongkul <arthit@gmail.com>

Author: bact

README.md

@@ -4,22 +4,29 @@ Stores SPDX documents in SPDX version 3 compatible JSON-LD format.
 
 This library utilizes the [SPDX Java Library Storage Interface](https://github.com/spdx/Spdx-Java-Library#storage-interface) extending the `ExtendedSpdxStore` which allows for utilizing any underlying store which implements the [SPDX Java Library Storage Interface](https://github.com/spdx/Spdx-Java-Library#storage-interface).
 
-# Code quality badges
+The API documentation is available at:
+<https://spdx.github.io/spdx-java-v3jsonld-store/>
 
-|   [![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store) | [![Bugs](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=bugs)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)   | [![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=security_rating)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store) | [![Maintainability Rating](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=sqale_rating)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store) | [![Technical Debt](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=sqale_index)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store) |
+## Code quality badges
 
-# Using the Library
+[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)
+[![Bugs](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=bugs)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)
+[![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=security_rating)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)
+[![Maintainability Rating](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=sqale_rating)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)
+[![Technical Debt](https://sonarcloud.io/api/project_badges/measure?project=spdx-v3jsonld-store&metric=sqale_index)](https://sonarcloud.io/summary/new_code?id=spdx-v3jsonld-store)
+
+## Using the Library
 
 This library is intended to be used in conjunction with the [SPDX Java Library](https://github.com/spdx/Spdx-Java-Library).
 
 Create an instance of a store which implements the [SPDX Java Library Storage Interface](https://github.com/spdx/Spdx-Java-Library#storage-interface).  For example, the [InMemSpdxStore](https://github.com/spdx/Spdx-Java-Library/blob/master/src/main/java/org/spdx/storage/simple/InMemSpdxStore.java) is a simple in-memory storage suitable for simple file serializations and deserializations.
 
-Create an instance of `JsonLDStore(IModelStore baseStore, boolean pretty)` passing in the instance of a store created above along with the format.  If true, `pretty` will produce more human readable output including indents as well as license expressions rather than full model license details.
+Create an instance of `JsonLDStore(IModelStore baseStore, boolean pretty)` passing in the instance of a store created above along with the format.  If true, `pretty` will produce more human-readable output including indents as well as license expressions rather than full model license details.
 
-# Serializing and Deserializing
+## Serializing and Deserializing
 
 This library supports the `ISerializableModelStore` interface for serializing and deserializing files.
 
-# Development Status
+## Development Status
 
-Still in development, somewhat unstable.
+Still in development, somewhat unstable.