Update wellKnown URL for plone/.github

Requires plone/.github#13 to be merged first

Author: stevepiercy

frontend/public/funding.json

@@ -24,7 +24,7 @@
       },
       "repositoryUrl": {
         "url": "https://github.com/plone/.github",
-        "wellKnown": "https://github.com/plone/.github/.well-known/funding-manifest-urls"
+        "wellKnown": "https://github.com/plone/.github/blob/main/.well-known/funding-manifest-urls"
       },
       "licenses": [
         "spdx:GPL-2.0-only",