ci/github-script/prepare: refactor

Using core.info instead of console.log and simplifying the arguments for
API calls a bit.

ci/github-script/prepare.js

@@ -1,18 +1,19 @@
-module.exports = async ({ github, context, core }) => {
+module.exports = async function ({ github, context, core }) {
+  const pull_number = context.payload.pull_request.number
+
   for (const retryInterval of [5, 10, 20, 40, 80]) {
-    console.log('Checking whether the pull request can be merged...')
+    core.info('Checking whether the pull request can be merged...')
     const prInfo = (
       await github.rest.pulls.get({
-        owner: context.repo.owner,
-        repo: context.repo.repo,
-        pull_number: context.payload.pull_request.number,
+        ...context.repo,
+        pull_number,
       })
     ).data
 
     if (prInfo.state !== 'open') throw new Error('PR is not open anymore.')
 
     if (prInfo.mergeable == null) {
-      console.log(
+      core.info(
         `GitHub is still computing whether this PR can be merged, waiting ${retryInterval} seconds before trying again...`,
       )
       await new Promise((resolve) => setTimeout(resolve, retryInterval * 1000))
@@ -22,31 +23,29 @@ module.exports = async ({ github, context, core }) => {
     let mergedSha, targetSha
 
     if (prInfo.mergeable) {
-      console.log('The PR can be merged.')
+      core.info('The PR can be merged.')
 
       mergedSha = prInfo.merge_commit_sha
       targetSha = (
         await github.rest.repos.getCommit({
-          owner: context.repo.owner,
-          repo: context.repo.repo,
+          ...context.repo,
           ref: prInfo.merge_commit_sha,
         })
       ).data.parents[0].sha
     } else {
-      console.log('The PR has a merge conflict.')
+      core.warning('The PR has a merge conflict.')
 
       mergedSha = prInfo.head.sha
       targetSha = (
         await github.rest.repos.compareCommitsWithBasehead({
-          owner: context.repo.owner,
-          repo: context.repo.repo,
+          ...context.repo,
           basehead: `${prInfo.base.sha}...${prInfo.head.sha}`,
         })
       ).data.merge_base_commit.sha
     }
 
-    console.log(
-      `Checking the commits:\nmerged:${mergedSha}\ntarget:${targetSha}`,
+    core.info(
+      `Checking the commits:\nmerged: ${mergedSha}\ntarget: ${targetSha}`,
     )
     core.setOutput('mergedSha', mergedSha)
     core.setOutput('targetSha', targetSha)