Pin multibuild scripts to get manylinux1 wheels back

[jtattermusch]

Hotfix for #9180.

See #9180 (comment) for more context.

[jtattermusch]

For future reference, the manylinux version can be set by setting
MB_ML_VER=1 when invoking the build_wheel. But in our case it should only be done for x86_64 artifacts (aarch64 is only supported starting from manylinux2014)
https://github.com/matthew-brett/multibuild/blob/b89bb903e94308be79abefa4f436bf123ebb1313/travis_linux_steps.sh#L71

[haberman]

Thanks Jan!

It looks like the Linux Python Release job failed, perhaps because this version of multibuild doesn't support Python 3.10?

ls: /opt/python/cp310-cp310/bin: No such file or directory

[jtattermusch]

Thanks Jan!

It looks like the Linux Python Release job failed, perhaps because this version of multibuild doesn't support Python 3.10?

ls: /opt/python/cp310-cp310/bin: No such file or directory

Ok. I updated the PR:

• I pinned multibuild at the last version that's currently available.
• now setting MB_ML_VER explicitly for linux artifacts.

[jtattermusch]

Thanks Jan!

It looks like the Linux Python Release job failed, perhaps because this version of multibuild doesn't support Python 3.10?

ls: /opt/python/cp310-cp310/bin: No such file or directory

Ok, I know what the problem is. It's not about multibuild version.

The issue is that manylinux1 doesn't have python3.10 support (and I assume it will never have it because it's too old).
The docker image quay.io/pypa/manylinux1_x86_64:latest only has python versions up to 3.9.

So for python3.10 we will need to opt for a newer version of manylinux image (which one? manylinux2010 or manylinux2014?)

[jtattermusch]

@acozzette @haberman which manylinux version should we use for python3.10? We need to decide on that otherwise this PR will be stuck indefinitely.

[acozzette]

I'm not very familiar with all this but I would vote for 2014 just because 2010 sounds pretty old at this point.

[haberman]

Can we try 2010? I think older is better here, since it increases our compatibility.

[acozzette]

2010 sounds good to me.

[jtattermusch]

I updated the python3.10 wheel build to use manylinux2010. Let's see what the tests say. If they pass, I think this PR is good to go.

[jtattermusch]

Details

The wheels built by "Linux Python Release" job look good IMHO:
https://source.cloud.google.com/results/invocations/8f596554-2526-4504-9988-4123cff7b979/details