Environment variables do not work when using cmd in tasks

[nicornk]

Checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pixi, using pixi --version.

Reproducible example

Task:

just-test = { cmd = [    
    "export STACK_NAME=fargate-batch-job",
    "&&",
    "echo $STACK_NAME"

] }

pixi run just-test
✨ Pixi task (ci): "export STACK_NAME=fargate-batch-job" && "echo $STACK_NAME"
export STACK_NAME=fargate-batch-job: command not found

Available tasks:
        build-wheel
        deploy
        download_database
        just-test
        just-test-2
        postinstall-production
        start
        test
(grayskull) (base) ➜  oligo 

Task:

just-test-2 = "export STACK_NAME=fargate-batch-job && echo $STACK_NAME"

✨ Pixi task (ci): export STACK_NAME=fargate-batch-job && echo $STACK_NAME
fargate-batch-job
(grayskull) (base) ➜  oligo 

Issue description

It seems that export / referencing environment variables in the "cmd" way to define tasks is not working as expected.

Expected behavior

Both examples should work the same way.

[ruben-arts]

This is actually because of this issue: #837

So will close it, in favor of that.

For now, either use the multi-line toml notation or separate per word in an array.

just-test = { cmd = """
    export STACK_NAME=fargate-batch-job
    &&
    echo $STACK_NAME
"""}
just-test2 = { cmd = [    
    "export",  "STACK_NAME=fargate-batch-job",
    "&&",
    "echo", "$STACK_NAME"
] }

[nicornk]

ty for the quick reply!