Build fails after Poetry 1.2.0 release

[DrAhmetK]

GET_POETRY_IGNORE_DEPRECATION=1 doesn't help as well

-----> Building on the Heroku-22 stack
-----> Using buildpacks:
1. https://github.com/moneymeets/python-poetry-buildpack.git
2. heroku/python
3. https://github.com/heroku/heroku-buildpack-cli
-----> Python Poetry app detected
-----> Using Poetry version from POETRY_VERSION config var: 1.1.13
-----> Generate requirements.txt with Poetry
-----> Install Poetry
Retrieving Poetry metadata

   This installer is deprecated, and cannot install Poetry 1.2.0a1 or newer.
   Additionally, Poetry installations created by this installer cannot `self update` to 1.2.0a1 or later.
   You should migrate to https://install.python-poetry.org instead. Instructions are available at https://python-poetry.org/docs/#installation.
   
   This installer will now exit. If you understand the above warning and wish to proceed anyway, set GET_POETRY_IGNORE_DEPRECATION=1 in the environment and run this installer again.

-----> Export requirements.txt from Poetry
/tmp/codon/tmp/buildpacks/6e1a99cb61ad645328dd1c64bd71597add4e2b5b/bin/compile: line 66: poetry: command not found
! Push rejected, failed to compile Python Poetry app.
! Push failed

[djm]

This is a dupe of #37; a PR has already been opened at #44

[zyv]

Resolved in #48.