Persisting environment data between steps not working with debian base image

[micash545]

Component

server

Describe the bug

steps:
  - name: init
    image: debian
    commands:
      - echo "FOO=hello" >> envvars
      - echo "BAR=world" >> envvars

  - name: debug
    image: debian
    commands:
      - source envvars
      - echo $FOO

Output of debig step:

+ source envvars
/bin/sh: 15: source: not found

System Info

{"source":"https://github.com/woodpecker-ci/woodpecker","version":"2.3.0"}

Additional context

No response

Validations

• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Checked that the bug isn't fixed in the next version already [https://woodpecker-ci.org/faq#which-version-of-woodpecker-should-i-use]

[zc-devs]

1. Use POSIX . envvars;
2. Or wait for Rework entrypoints #3269;
3. Or try to wrap in script:

  - name: debug
    commands:
      - cicd/debug.sh
    image: debian

#!/bin/bash
source envvars
echo $FOO