poetry installer (get-poetry.py) had deprecated

[masaki925]

ref: python-poetry/poetry#6377

when you build, you get error:

Step #0: Step 5/16 : RUN curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python
Step #0:  ---> Running in 3cab2b4e324f
Step #0: Retrieving Poetry metadata
Step #0: 
Step #0: This installer is deprecated, and scheduled for removal from the Poetry repository on or after January 1, 2023.
Step #0: See https://github.com/python-poetry/poetry/issues/6377 for details.
Step #0: 
Step #0: You should migrate to https://install.python-poetry.org instead, which supports all versions of Poetry, and allows for `self update` of versions 1.1.7 or newer.
Step #0: Instructions are available at https://python-poetry.org/docs/#installation.
Step #0: 
Step #0: Without an explicit version, this installer will attempt to install the latest version of Poetry.
Step #0: This installer cannot install Poetry 1.2.0a1 or newer (and installs will be unable to `self update` to 1.2.0a1 or newer).
Step #0: 
Step #0: To continue to use this deprecated installer, you must specify an explicit version with --version <version> or POETRY_VERSION=<version>.
Step #0: Alternatively, if you wish to force this deprecated installer to use the latest installable release, set GET_POETRY_IGNORE_DEPRECATION=1.
Step #0: 
Step #0: Version 1.2.0 is not supported by this installer! Please specify a version prior to 1.2.0a1 to continue!
Step #0: The command '/bin/sh -c curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python' returned a non-zero code: 1
Finished Step #0
ERROR
ERROR: build step 0 "gcr.io/cloud-builders/docker" failed: step exited with non-zero status: 1

and also, --no-dev had deprecated:

 => ERROR [build_base 8/8] RUN poetry install --no-dev                                                                                                                                                            5.1s
------
 > [build_base 8/8] RUN poetry install --no-dev:
#13 0.876 Skipping virtualenv creation, as specified in config file.
#13 1.052 The `--no-dev` option is deprecated, use the `--only main` notation instead.
#13 2.603 Installing dependencies from lock file
...
------
executor failed running [/bin/sh -c poetry install --no-dev]: exit code: 1

[AseiSugiyama]

Thanks for reporting!

[AseiSugiyama]

We will fix this by using curl -sSL https://install.python-poetry.org instead of get-poetry.py