Fix typo (#2155)

Author: n1ru4l

.github/stale.yml

@@ -11,7 +11,7 @@ exemptLabels:
   - high-priority
 # text of the comment when marking issue as stale
 markComment: >
-  This issue has been automatically marked as stale becuase it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions to Apollo Client!
+  This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions to Apollo Client!
 # text of the comment when closing an issue
 closeComment: >
   This issue has been automatically closed because it has not had recent activity after being marked as stale. If you belive this issue is still a problem or should be reopened, please reopen it! Thank you for your contributions to Apollo Client!