change function name to match file name

Author: talha-API

test/test_jwe_encryption.rb

@@ -85,8 +85,8 @@ def test_decrypt_field_level
     assert !decrypted['body']['encrypted_payload']
   end
 
-  def test_decrypt_gcm
-    resp = File.read('./test/mock/jwe-response-gcm.json')
+  def test_decrypt_a256gcm
+    resp = File.read('./test/mock/jwe-response-a256gcm.json')
     jwe = McAPI::Encryption::JweEncryption.new(@test_config)
     decrypted = JSON.parse(jwe.decrypt(resp))
     assert_equal decrypted['body']['mapping']['customer_identifier'], 'CUST_12345'