[CI] No module named pytest

[Liam-Sturge]

Summary:

When attempting to test a built / repaired wheel using the script /wheel/run_tests.sh an error occurs stating that pytest is not an installed module.

Failing Command:

./docker/bash.sh --no-gpu tlcpack/package-cpu:2fddbe0 ./wheel/run_tests.sh

Example Error Output:

python3 -m pytest -o \
 junit_suite_name=python-unittest-platform-minimal-test-0-no-shard-ctypes \
 --junit-xml=/workspace/tvm/build/pytest-results/python-unittest-platform-minimal-test-0-no-shard-ctypes.xml \
 --junit-prefix=ctypes tests/python/all-platform-minimal-test -n=1

/opt/conda/bin/python3: No module named pytest