fix: revert to github-script v6 (#913)

Author: MaxFrank13

.github/workflows/create_credentials_requirements_pr.yml

@@ -45,7 +45,7 @@ jobs:
 
       # Create a PR and comment on original PR
       - name: create PR
-        uses: actions/github-script@v7
+        uses: actions/github-script@v6
         with:
           github-token: ${{secrets.REQUIREMENTS_BOT_GITHUB_TOKEN}}
           script: |
@@ -58,7 +58,7 @@ jobs:
               base: 'master',
             })
             // Get the PR that relates to the tagged commit
-            const getRelatedPrResponse = await github.rest.repos.listPullRequestsAssociatedWithCommit.endpoint.merge({
+            const getRelatedPrResponse = await github.rest.repos.listPullRequestsAssociatedWithCommit({
               owner: 'edx',
               repo: 'credentials-themes',
               commit_sha: process.env.GITHUB_SHA