i#4953 ubuntu20: Update package building to use Ubuntu 20

Upgrades the VM's used for package building from Ubuntu 16.04 to Ubuntu 20.04.

Issue: #4953 (closed)

Running a test package build now: https://github.com/DynamoRIO/dynamorio/actions/runs/1242068139

The package succeeded: https://github.com/DynamoRIO/dynamorio/releases/tag/cronbuild-8.0.18886 I downloaded the Linux tarball and ran the commands in the README as a sanity check on my laptop and it worked; a better test would be to run on an old Linux with old libc, since that's likely where issues would come in from building on a new Linux with a new libc. But we don't have enough developer resources to be so thorough; I would say let's rely on users on old machines to complain to figure this out.

requested review from @abhinav92003

approved this merge request

Merged by: derekbruening at 2021-09-16 16:14:21 UTC

closed