feat: added where method in AssetLibrary class

Author: reeshika-h

src/main/java/com/contentstack/sdk/AssetLibrary.java

@@ -208,4 +208,11 @@ public enum ORDERBY {
         ASCENDING, DESCENDING
     }
 
+    public AssetLibrary where(String key, String value) {
+        JSONObject queryParams= new JSONObject();
+        queryParams.put(key,value);
+        urlQueries.put("query", queryParams);
+        return this;
+    }
+ 
 }

src/test/java/com/contentstack/sdk/TestAssetLibrary.java

@@ -2,6 +2,9 @@
 
 import org.junit.jupiter.api.*;
 
+import com.google.gson.JsonObject;
+import org.json.*;
+
 import java.util.List;
 import java.util.logging.Logger;
 
@@ -95,4 +98,15 @@ void testIncludeOwner() {
         AssetLibrary assetLibrary = stack.assetLibrary().includeMetadata();
         Assertions.assertFalse(assetLibrary.headers.containsKey("include_owner"));
     }
+
+    @Test
+    void testAssetQueryOtherThanUID() {
+    AssetLibrary query = stack.assetLibrary().where("tags","tag1");
+    query.fetchAll(new FetchAssetsCallback() {
+        @Override
+        public void onCompletion(ResponseType responseType, List<Asset> assets, Error error) {
+          System.out.println(assets);
+        }
+    });
+    }
 }