Upgrade to Python 3.10

[achimnol]

Python 3.10.0 is live now.
Let's upgrade our codebase (the 21.03/21.09 branch and the main branch for 22.03) to use Python 3.10 for future backportability.

Currently known blockers:

• bpo-45416: Fix use of asyncio.Condition() with explicit Lock objects python/cpython#28850 (expected to land in 3.10.1)
• Error with Python 3.10: "ValueError: loop argument must agree with lock" aio-libs/janus#358
• Request for Python 3.10.1 support actions/setup-python#299
• Push collections.abc deprecation warning fix to pypi syrusakbary/aiodataloader#16 (merged but not released, the maintainer seems to have gone...) forked and released as aiodataloader-ng
• Support Python 3.10 achimnol/aiotools#28
• Support for python 3.10 match statement python/mypy#10191 (expected to land in 0.940)
• [Python][macOS] 3.10 wheel is mislabeled as universal2 grpc/grpc#28387
  • Mitigated by installer: Fix up grpcio install issue on M1 and Python 3.10 #391

Not blockers but considerable stuffs for seamless development experience:

• Support for PEP 622 structural pattern matching vim-python/python-syntax#80

[achimnol]

janus 0.6.2 has been released with the workaround for Python 3.10. Now we can start working on this issue.

[achimnol]

Currently GitHub Action Runner supports only 3.10.0, not 3.10.1 that we need. On hold.

[achimnol]

GitHub Action Runner now provides 3.10.1.
Also fixed some new typing errors found by mypy 0.920 update (lablup/backend.ai-common#104).

[achimnol]

Forked aiodataloader as aiodataloader-ng.

[achimnol]

Released our own version of aiodataload-ng: https://pypi.org/project/aiodataloader-ng/0.2.1/

[kyujin-cho]

newly investigated upstream issues:

• [Python][macOS] 3.10 wheel is mislabeled as universal2 grpc/grpc#28387

[achimnol]

newly investigated upstream issues:

• [Python][macOS] 3.10 wheel is mislabeled as universial2 grpc/grpc#28387

Currently the known workaround is to execute the followings in the target venv:

pip install --no-binary :all: grpcio --ignore-installed
pip install --no-binary :all: grpcio-tools --ignore-installed

[achimnol]

After #417, we now work fine on Pytho 3.10.5 and now all external dependencies have upgraded to provide 3.10-compatible binary wheels (#560). The vim syntax support could be workarounded using NeoVim and treesitter.