Monorepo using Serverless Compose with serverless-python-requirements breaks plugin packaging

[david-a-jetter]

Issue description

I've also opened an issue in Serverless Compose: serverless/compose#152

I think this is ultimately an issue with this plugin though, with the expectation that the pyproject.toml file is in the same directory as the serverless.yml file that's being deployed.

Use case: A Python monorepo with all pypi requirements managed through Poetry in a single pyproject.toml file, containing multiple Serverless services, each using serverless-python-requirements plugin being migrated from serialized serverless deploy commands to Serverless Compose. After moving each service's yml file into its own subdirectory, adding the requisite serverless-compose.yml in the root, and running npx sls deploy, each package's zip file contains just the source code and no python packages. The serverless-python-requirements plugin did not run at all.

Expected Behavior: The source code matching the package.patterns is included, as well as all non-dev python dependencies produced by serverless-python-requirements are included.

Actual Behavior: Only the source code matching the package.patterns is included, but the serverless-python-requirements plugin does not run.

The repository structure is roughly outlined as:

pyproject.toml
poetry.lock
serverless-compose.yml
src/
package/
  - appone/
    - serverless.appone.yml
  - apptwo/
    - serverless.apptwo.yml
  - appthree/
    - serverless.appthree.yml

Workaround: Use copyfiles npm package (which ensures cross-platform compatibility) to copy the pyproject.toml file into each app's subdirectory, eg: npx copyfiles pyproject.toml poetry.lock package/appone before running npx sls deploy and the serverless-python-requirements plugin behaves as expected.

Service configuration (serverless-compose.yml) content

services:
  appone:
    path: package/appone
    config: serverless.appone.yml
  apptwo:
    path: package/apptwo
    config: serverless.apptwo.yml
  appthree:
    path: package/appthree
    config: serverless.appthree.yml