Update the list_pull_request 401 case (#89)

* Update the list_pull_request 401 case
Hi, I find this http request is also missing the 401 case.
* Update CHANGELOG.md

CHANGELOG.md

@@ -14,6 +14,7 @@ represented by the pull requests that fixed them. Critical items to know are:
 Versions correspond with GitHub releases that can be referenced with @ using actions.
 
 ## [master](https://github.com/vsoch/pull-request-action/tree/master) (master)
+  - bugfix of token handling if 401 error received (missing 401 case) (1.0.21)
   - bugfix of writing to environment file (missing newline) (1.0.19)
   - bugfix of missing from branch with scheduled run (1.0.16)
   - forgot to add assignees (1.0.15)

pull-request.py

@@ -180,8 +180,8 @@ def list_pull_requests(target, source):
     print("Params for checking if pull request exists: %s" % params)
     response = requests.get(PULLS_URL, params=params)
 
-    # Case 1: 404 might warrant needing a token
-    if response.status_code == 404:
+    # Case 1: 401, 404 might warrant needing a token
+    if response.status_code in [401, 404]:
         response = requests.get(PULLS_URL, params=params, headers=HEADERS)
     if response.status_code != 200:
         abort_if_fail(response, "Unable to retrieve information about pull requests")
@@ -238,7 +238,7 @@ def find_default_branch():
     """Find default branch for a repo (only called if branch not provided)"""
     response = requests.get(REPO_URL)
 
-    # Case 1: 404 might need a token
+    # Case 1: 401, 404 might need a token
     if response.status_code in [401, 404]:
         response = requests.get(REPO_URL, headers=HEADERS)
     if response.status_code != 200: