fixed the pinning of torch in requirements.txt and conda recipe

conda/meta.yaml

@@ -29,7 +29,7 @@ requirements:
     - bob.core
     - bob.io.base
     - bob.io.image
-    - pytorch =0.4
+    - pytorch >=0.4
     - torchvision >=0.2.0
   run:
     - python

requirements.txt

@@ -6,5 +6,5 @@ bob.extension
 bob.core
 bob.io.base
 bob.io.image
-torch == 0.4.0
+torch >= 0.4.0
 torchvision >= 0.2.0