Pin kornia to prevent torch upgrade.

BUG=162850432

Author: rosbo

Dockerfile

@@ -343,7 +343,8 @@ RUN pip install bcolz && \
     pip install nbformat && \
     pip install notebook==5.5.0 && \
     pip install olefile && \
-    pip install kornia && \
+    # b/162850432 unpin once we upgrade to pytorch 1.6
+    pip install kornia==0.3.2 && \
     pip install pandas_summary && \
     pip install pandocfilters && \
     pip install pexpect && \