Jitpack build broken due to python3 switch

Sample log: https://jitpack.io/com/github/facebook/buck/3e23794873/build.log

Relevant lines:

BUILD SUCCESSFUL
Total time: 1 minute 7 seconds
+++ bin/buck build buck --show-output
+++ awk '{print $2}'
Not using buckd because watchman isn't installed.
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF-8 -Dhttps.protocols=TLSv1.2
PARSING BUCK FILES: FINISHED IN 0.8s
CREATING ACTION GRAPH: FINISHED IN 0.1s
DOWNLOADED 0 ARTIFACTS, 0.00 BYTES, 0.0% CACHE MISS
BUILDING: FINISHED IN 1.1s
BUILD FAILED
No python interpreter found (searched python3).
    When creating rule //py/hash:hash_files.
++ PEX=
2020-02-08T06:34:20.044197191Z
Exit code: 1