🐛 Fix broken manylinux wheels (#310)

## Description

Due to the way Linux wheels are built by cibuildwheel (in a manylinux
docker container), environment varaiables are not passed down to the
container. As a result the `CI` environment variable is not defined in
the docker container, which is used to flip on the `DEPLOY` CMake
setting automatically.
This has lead to manylinux wheels being built with `-march=native` that
might produce errors like
```console
Illegal instruction (core dumped)
```
when trying to import the respective packages.

This PR fixes this by making sure that `DEPLOY="ON"` within
cibuildwheel.

## Checklist:

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- [x] The pull request only contains commits that are related to it.
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- [x] The pull request introduces no new warnings and follows the
project's style guidelines.

Signed-off-by: burgholzer <[email protected]>

pyproject.toml

@@ -240,6 +240,7 @@ test-skip = "cp312-*"  # Qiskit Terra does not support Python 3.12 yet
 build-frontend = "build"
 
 [tool.cibuildwheel.linux]
+environment = { DEPLOY="ON" }
 
 [tool.cibuildwheel.macos]
 environment = { MACOSX_DEPLOYMENT_TARGET = "10.15" }