Bug 1574050 [wpt PR 18442] - [Azure Pipelines] Migrate scheduled buil…

…ds to YAML, a=testonly

Automatic update from web-platform-tests
[Azure Pipelines] Migrate scheduled builds to YAML (#18442)

Based on another migration which worked:
foolip/safari-technology-preview-updater@259eff3

Fixes web-platform-tests/wpt#17342.
--

wpt-commits: b16bc5597bb9981c3bd29ca3209979df0c9c24fe
wpt-pr: 18442

UltraBlame original commit: d3ff9a191f89e8fcdc40fbd7b574be12eb06228a

testing/web-platform/tests/.azure-pipelines.yml

@@ -1,6 +1,7 @@
 # This is the configuration file for Azure Pipelines, used to run tests on
 # macOS. Documentation to help understand this setup:
 # https://docs.microsoft.com/en-us/azure/devops/pipelines/yaml-schema
+# https://docs.microsoft.com/en-us/azure/devops/pipelines/build/triggers
 # https://docs.microsoft.com/en-us/azure/devops/pipelines/process/multiple-phases
 # https://docs.microsoft.com/en-us/azure/devops/pipelines/process/templates
 # https://docs.microsoft.com/en-us/azure/devops/pipelines/process/variables
@@ -10,13 +11,20 @@
 # project is required:
 #  - The "Build pull requests from forks of this repository" setting must be
 #    enabled: https://docs.microsoft.com/en-us/azure/devops/pipelines/repos/github#validate-contributions-from-forks
-#  - A scheduled build needs to be set up for one of the epochs/* branches.
 #  - Self-hosted agents for Windows 10 are used:
 #    - 'Hosted Windows Client' is the latest Windows 10
 #    - 'Hosted Windows Client Next' is Windows 10 Insider Preview
 #    Documention for the setup of these agents:
 #    https://docs.microsoft.com/en-us/azure/devops/pipelines/agents/v2-windows
 
+schedules:
+- cron: "15 */6 * * *"
+  displayName: Every six hours
+  branches:
+    include:
+    - epochs/six_hourly
+  always: true
+
 jobs:
 # The affected tests jobs are unconditional for speed, as most PRs have one or
 # more affected tests: https://github.com/web-platform-tests/wpt/issues/13936.