update train_vocoder_gan.py for coqpit

tests/vocoder_tests/test_vocoder_melgan_generator.py

@@ -0,0 +1,14 @@
+import numpy as np
+import torch
+
+from TTS.vocoder.models.melgan_generator import MelganGenerator
+
+
+def test_melgan_generator():
+    model = MelganGenerator()
+    print(model)
+    dummy_input = torch.rand((4, 80, 64))
+    output = model(dummy_input)
+    assert np.all(output.shape == (4, 1, 64 * 256))
+    output = model.inference(dummy_input)
+    assert np.all(output.shape == (4, 1, (64 + 4) * 256))