Allow the e2e suites to be run manually against master (#833)

The three e2e jobs are gated on `github.event.pull_request.labels`, which
is empty for a push. They therefore skip on every push to master as well
as on every unlabelled pull request, so nothing has run them on master
for some time.

That matters most just before a release, when we want to know that the
commit we are about to tag actually passes end to end. Until now the only
way to get an e2e run was to open a pull request and label it, which
tests a merge commit rather than master itself.

Adding `workflow_dispatch` gives a Run workflow button that runs all
three suites against any ref, including master. The label route is
unchanged for pull requests.

Two things stay as they are:

- The GKE cluster cleanup guard reads the same missing labels field, so
  on a manual run it evaluates to true and the cluster is still deleted.
- The cluster name is derived from a timestamp, not the pull request, so
  it is already safe outside a pull request context.

Verified by labelling this PR: all three e2e suites ran and passed via
the existing label route, confirming the added condition does not break
it.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Richard Wall <richard.wall@cyberark.com>

Author: wallrj-cyberark

.github/workflows/tests.yaml

@@ -3,6 +3,10 @@ on:
   push:
     branches: [master]
   pull_request: {}
+  # Lets us run the e2e suites against master, which the label gates below
+  # cannot do: they read github.event.pull_request.labels, which is empty for
+  # a push. Needed before tagging a release.
+  workflow_dispatch: {}
 jobs:
   verify:
     runs-on: ubuntu-latest
@@ -80,7 +84,7 @@ jobs:
     # where the e2e fails with a 400 error relating to "conflicting tagging values"
     # The test is flaky, not broken and re-running eventually makes it pass - but that delays progress on
     # other unrelated work.
-    if: contains(github.event.pull_request.labels.*.name, 'test-ark')
+    if: github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'test-ark')
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
@@ -117,7 +121,7 @@ jobs:
 
   ngts-test-e2e:
     # TEMPORARY: require an explicit label to test NGTS until we have a stable test environment
-    if: contains(github.event.pull_request.labels.*.name, 'test-ngts')
+    if: github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'test-ngts')
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
@@ -151,7 +155,7 @@ jobs:
           NGTS_TSG_URL: https://1806660206.ngts.qa.venafi.io
 
   test-e2e:
-    if: contains(github.event.pull_request.labels.*.name, 'test-e2e')
+    if: github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'test-e2e')
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1