snapshot uploading: do upload the regular Git for Windows versions

A regular Git for Windows version is branch-deployed in a Pull Request:
It is built via the `/git-artifacts` slash command and then published
via the `/release` slash command.

Crucially, this build needs to be validated manually between the time
when the `git-artifacts` workflows are done and the time when they are
uploaded, and during that time window, the artifacts should _not_ be
published as snapshots because if validation fails, they need to be
rebuilt.

The preceding two commits fixed the bug where the `upload-snapshot`
workflow was run in that time window by mistake.

However, when _do_ we want to upload the freshly-built official version
as a new snapshot? Why, of course when the `main` branch is pushed.

Except that we do not push at all, the `/release` slash command just
updates the `main` ref, knowing fully well that no objects need to be
pushed because `main` must fast-forward to the the PR branch when
releasing a new Git for Windows version; This is enforced. And updating
the ref via the REST API does not trigger the `push` event at all.

Therefore we need to manually pretend that a `push` happened, and then
all will be good again.

Signed-off-by: Johannes Schindelin <[email protected]>

GitForWindowsHelper/finalize-g4w-release.js

@@ -58,5 +58,20 @@ module.exports = async (context, req) => {
         force: false // require fast-forward
     })
 
-    return `Took care of pushing the \`main\` branch to close PR ${prNumber}`
+    // trigger "upload artifacts" workflow
+    const { handlePush } = require('./cascading-runs')
+    const uploadSnapshotAnswer = await handlePush(context, {
+        body: {
+            repository: {
+                owner: {
+                    login: owner,
+                },
+                name: repo,
+            },
+            ref: 'refs/heads/main',
+            after: sha,
+        }
+    })
+
+    return `Took care of pushing the \`main\` branch to close PR ${prNumber}\n${uploadSnapshotAnswer}`
 }

__tests__/index.test.js

@@ -943,11 +943,14 @@ test('a completed `release-git` run updates the `main` branch in git-for-windows
     try {
         expect(await index(context, context.req)).toBeUndefined()
         expect(context.res).toEqual({
-            body: `Took care of pushing the \`main\` branch to close PR 765`,
+            body: [
+                'Took care of pushing the `main` branch to close PR 765',
+                `The 'tag-git' workflow run was started at dispatched-workflow-tag-git.yml`,
+            ].join('\n'),
             headers: undefined,
             status: undefined
         })
-        expect(mockGitHubApiRequest).toHaveBeenCalledTimes(4)
+        expect(mockGitHubApiRequest).toHaveBeenCalledTimes(7)
         expect(mockGitHubApiRequest.mock.calls[3].slice(1)).toEqual([
             'installation-access-token',
             'PATCH',