Test that overwrite env var works in nested action

[leonardovillela]

Description 📜

This PR introduces changes to add an E2E test to verify if it's possible to overwrite env vars value set before in a nested action. This test is nice to ensure we do not introduce this bug again as a regression in the future.

Closes #350

cc: @Zlaticanin

[hashicorp-cla]

All committers have signed the CLA.

[thyton]

Hey @leonardovillela, thanks for taking this on!
Based on #350, the expected behavior is described as the env var should have the new value after a subsequent call to vault-action. Perhaps, a simple enough approach to testing it could be the following. We don't need a separate action file for this approach.

• Creating another endpoint to secret/data that has a different secret value

await got(`http://${vaultUrl}/v1/secret/data/subsequent-test`, {
            method: 'POST',
            headers: {
                'X-Vault-Token': vaultToken,
            },
            json: {
                data: {
                    secret: 'SUBSEQUENT_TEST_SECRET',
                },
            },
        });

• Calling vault-action twice and reading secret/data/test and the new endpoint subsequently

- name: Test Vault Action Overwrites Env Vars In Subsequent Action (part 1/2)
      uses: ./
      with:
        url: http://localhost:8200/
        token: testtoken
        secrets: |
          secret/data/test secret | SUBSEQUENT_TEST_SECRET;
- name: Test Vault Action Overwrites Env Vars In Subsequent Action (part 2/2)
      uses: ./
      with:
        url: http://localhost:8200/
        token: testtoken
        secrets: |
          secret/data/subsequent-test secret | SUBSEQUENT_TEST_SECRET;

[leonardovillela]

Hi @thyton, thanks for your review 🙇

Based on #350, the expected behavior is described as the env var should have the new value after a subsequent call to vault-action.

On #350 the scenario described include also a new action that calls the vault-action, I tried to reproduce the exactly same scenario mentioned in the issue. But probably having this new action does not make that big difference, so I implemented your suggestion in 1d5aa91