Re-enable blank issues (#13468)

The TL;DR is that GitHub is enforcing blank_issues_enabled=false in the issue template configuration strictly (we used to use a direct URL as a bypass). This is a recent change. The core team uses blank issues extensively so we need to re-enable blank issues. Unfortunately, this has the side effect of allowing everyone to file blank issues. We'll simply have to see how much (if any) misfiled issues we get.

Author: ichard26

.github/ISSUE_TEMPLATE/config.yml

@@ -1,8 +1,8 @@
 # Documentation for this file can be found at:
 # https://help.github.com/en/github/building-a-strong-community/configuring-issue-templates-for-your-repository
 
-blank_issues_enabled: false
-contact_links:
-  - name: "(maintainers only) Blank issue"
-    url: https://github.com/pypa/pip/issues/new
-    about: For maintainers only.
+blank_issues_enabled: true
+# contact_links:
+#   - name: "(maintainers only) Blank issue"
+#     url: https://github.com/pypa/pip/issues/new
+#     about: For maintainers only.