Support to open pull request to another repo (#70)

* support custom token and repo
* print post url if there's error
* update as comments
* Update README.md

Co-authored-by: Vanessasaurus <814322+vsoch@users.noreply.github.com>

pull-request.py

@@ -108,6 +108,7 @@ def open_pull_request(title, body, target, source, is_draft=False, can_modify=Tr
     print("Data for opening pull request: %s" % data)
     response = requests.post(PULLS_URL, json=data, headers=HEADERS)
     if response.status_code != 201:
+        print(f"pull request url is {PULLS_URL}")
         abort_if_fail(response, "Unable to create pull request")
 
     return response
@@ -268,14 +269,17 @@ def add_reviewers(entry, reviewers, team_reviewers):
 API_VERSION = "v3"
 BASE = "https://api.github.com"
 
+PR_TOKEN = os.environ.get("PULL_REQUEST_TOKEN") or get_envar("GITHUB_TOKEN")
+PR_REPO = os.environ.get("PULL_REQUEST_REPOSITORY") or get_envar("GITHUB_REPOSITORY")
+
 HEADERS = {
-    "Authorization": "token %s" % get_envar("GITHUB_TOKEN"),
+    "Authorization": "token %s" % PR_TOKEN,
     "Accept": "application/vnd.github.%s+json;application/vnd.github.antiope-preview+json;application/vnd.github.shadow-cat-preview+json"
     % API_VERSION,
 }
 
 # URLs
-REPO_URL = "%s/repos/%s" % (BASE, get_envar("GITHUB_REPOSITORY"))
+REPO_URL = "%s/repos/%s" % (BASE, PR_REPO)
 ISSUE_URL = "%s/issues" % REPO_URL
 PULLS_URL = "%s/pulls" % REPO_URL