feat: gcp support implementation

Author: harshithad0703

.gitignore

@@ -45,3 +45,6 @@ lib/
 src/androidTest/java/com/builtio/contentstack/ApplicationTest.java
 src/main/res/
 contentstack/src/androidTest/java/com/contentstack/sdk/SyncTestCase.java
+
+# key file
+key.keystore

contentstack/src/androidTest/java/com/contentstack/sdk/AssetTestCase.java

@@ -178,4 +178,17 @@ public void test_AZURE_NA() throws Exception {
         stack = Contentstack.stack(appContext, DEFAULT_API_KEY, DEFAULT_DELIVERY_TOKEN, DEFAULT_ENV, config);
     }
 
+    @Test
+    public void test_GCP_NA() throws Exception {
+        Config config = new Config();
+        String DEFAULT_API_KEY = BuildConfig.APIKey;
+        String DEFAULT_DELIVERY_TOKEN = BuildConfig.deliveryToken;
+        String DEFAULT_ENV = BuildConfig.environment;
+        String DEFAULT_HOST = BuildConfig.host;
+        config.setHost(DEFAULT_HOST);
+        config.setRegion(Config.ContentstackRegion.GCP_NA);
+        Context appContext = InstrumentationRegistry.getTargetContext();
+        stack = Contentstack.stack(appContext, DEFAULT_API_KEY, DEFAULT_DELIVERY_TOKEN, DEFAULT_ENV, config);
+    }
+
 }

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

@@ -52,6 +52,7 @@ public void setBranch(String branch) {
      *                                                         config.setRegion(ContentstackRegion.EU);
      *                                                         config.setRegion(ContentstackRegion.AZURE_EU);
      *                                                         config.setRegion(ContentstackRegion.AZURE_NA);
+     *                                                         config.setRegion(ContentstackRegion.GCP_NA);
      *                                                         }
      *                                                         </pre>
      */
@@ -77,7 +78,7 @@ public Config earlyAccess(String[] earlyAccess) {
         return this;
     }
 
-    public enum ContentstackRegion {US, EU, AZURE_NA, AZURE_EU}
+    public enum ContentstackRegion {US, EU, AZURE_NA, AZURE_EU, GCP_NA}
 
     /**
      * Config constructor