[CI] Fix release uploads (#466)

### Summary:

Modify the release package uploader to avoid uploading duplicate packages

### Test Plan:

CI + test release to ensure that release packages are uploaded correctly

build/upload_release.py

@@ -54,20 +54,23 @@ def upload():
         )
 
     # For each OS: For each backend version: For each CPU/GPU:
-    upload_package("source/bazel-bin/neuropod/backends/tensorflow/neuropod_tensorflow_backend.tar.gz", release_id, "{}-tensorflow-{}-backend.tar.gz".format(platform, REQUESTED_TF_VERSION))
     upload_package("source/bazel-bin/neuropod/backends/torchscript/neuropod_torchscript_backend.tar.gz", release_id, "{}-torchscript-{}-backend.tar.gz".format(platform, REQUESTED_TORCH_VERSION))
 
-    # The python package is the same across CPU/GPU and different versions of backends so we'll only upload once for mac and once for linux
-    # For each OS: For each python version
-    if not IS_GPU:
-        # Upload the pythonbridge backend
-        upload_package("source/bazel-bin/neuropod/backends/python_bridge/neuropod_pythonbridge_backend.tar.gz", release_id, "{}-python-{}-backend.tar.gz".format(platform, PYTHON_VERSION))
-
-        # Upload the wheels
-        for gpath in ["source/python/dist/neuropod-*.whl"]:
-            whl_path = glob.glob(gpath)[0]
-            fname = os.path.basename(whl_path)
-            upload_package(whl_path, release_id, fname, content_type="application/zip")
+    # Only upload these once
+    if REQUESTED_TORCH_VERSION != "1.6.0" and REQUESTED_TORCH_VERSION != "1.7.0":
+        upload_package("source/bazel-bin/neuropod/backends/tensorflow/neuropod_tensorflow_backend.tar.gz", release_id, "{}-tensorflow-{}-backend.tar.gz".format(platform, REQUESTED_TF_VERSION))
+
+        # The python package is the same across CPU/GPU and different versions of backends so we'll only upload once for mac and once for linux
+        # For each OS: For each python version
+        if not IS_GPU:
+            # Upload the pythonbridge backend
+            upload_package("source/bazel-bin/neuropod/backends/python_bridge/neuropod_pythonbridge_backend.tar.gz", release_id, "{}-python-{}-backend.tar.gz".format(platform, PYTHON_VERSION))
+
+            # Upload the wheels
+            for gpath in ["source/python/dist/neuropod-*.whl"]:
+                whl_path = glob.glob(gpath)[0]
+                fname = os.path.basename(whl_path)
+                upload_package(whl_path, release_id, fname, content_type="application/zip")
 
 def get_release_id(tag_name):
     # https://api.github.com/repos/uber/neuropod/releases/tags/{tag_name}