Allow running tests from fork (#1945)

* Test running integration tests from PR

* integration-test

* use labels

* Allow integration tests on forks

* Allow manual trigger in fork

* Update contributing docs

.github/workflows/integration-tests.yml

@@ -18,7 +18,7 @@ on:
   workflow_dispatch:
 jobs:
   integration-tests:
-    if: github.repository_owner == 'Qiskit'
+    if: github.event_name == 'workflow_dispatch' || github.repository_owner == 'Qiskit'
     name: Run integration tests - ${{ matrix.environment }}
     runs-on: ${{ matrix.os }}
     strategy:

CONTRIBUTING.md

@@ -219,7 +219,9 @@ QISKIT_IBM_INSTANCE=crn:v1:bluemix:...                          # The CRN value
 To enable test cases against external system in your private fork, make sure to set above values as
 [encrypted environment secrets](https://docs.github.com/en/actions/security-guides/encrypted-secrets#creating-encrypted-secrets-for-an-environment).
 The names of the environments must match the ones that the [CI workflow](.github/workflows/ci.yml) relies
-upon.
+upon. 
+
+For example, in your github fork settings, add the environment you want to run tests on (ibm-quantum-production, ibm-quantum-staging, ibm-cloud-production, ibm-cloud-staging). Then add the appropriate environment secrets (QISKIT_IBM_INSTANCE, QISKIT_IBM_TOKEN, QISKIT_IBM_URL, QISKIT_IBM_DEVICE).
 
 ### Style guide