As per [github](https://github.com/actions/virtual-environments/issues/3287), this is no longer supported. CI fails with errors like
```
This request was automatically failed because there were no enabled runners online to process the request for more than 1 days.
```
I will add 20.04 in a followup PR to match `publish.yml`. Want to keep it separate in case adding 20.04 causes issues, removing 16.04 should be much less likely to.
runs-on: ${{ matrix.os }}
strategy:
matrix:
- os: [ubuntu-16.04, ubuntu-18.04] # 16.04.4 release has 4.15 kernel
- # 18.04.3 release has 5.0.0 kernel
+ os: [ubuntu-18.04] # 18.04.3 release has 5.0.0 kernel
env:
- TYPE: Debug
PYTHON_TEST_LOGFILE: critical.log