Fix transformers version

requirements.txt

@@ -1,7 +1,7 @@
 git+git://github.com/learning-at-home/hivemind@dalle-v1
 git+git://github.com/learning-at-home/dalle-pytorch@weight-sharing
 bitsandbytes-cuda111>=0.26.0
-transformers>=4.9.2
+transformers==4.12.2
 tokenizers>=0.10.2
 datasets>=1.11.0
 torch_optimizer>=0.1.0
@@ -10,4 +10,4 @@ nltk>=3.6.2
 sentencepiece
 aiohttp
 requests>=2.24.0
-termcolor
+termcolor