Fix set-milestone failure when latest milestone is closed

There can be situation where the latest milestone is closed but there
are still some PRs for which this workflow is pending. The  API by
default only lists open milestones. This commit changes it to list all
milestones so that even if the target milestone is closed it can be
found and the PR added to it.

This is correct reimplementation of
c38490b.

.github/workflows/milestone.yml

@@ -50,9 +50,14 @@ jobs:
             } = process.env
             console.log('Milestone number to set', MILESTONE_NUMBER)
 
-            // Find milestone
-            const response = await github.rest.issues.listMilestones(context.repo)
-            let milestone = response.data.find(milestoneResponse => milestoneResponse.title === MILESTONE_NUMBER)
+            // Find milestone with matching title
+            // See https://octokit.github.io/rest.js/v19#pagination
+            const milestones = await github.paginate(github.rest.issues.listMilestones, {
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                state: 'all'
+            })
+            let milestone = milestones.find(milestone => milestone.title === MILESTONE_NUMBER)
             console.log('Found milestone with title', MILESTONE_NUMBER, milestone)
 
             // Create new milestone if it doesn't exist