ci: Run linkcheck once a week instead of every PR

Resolves #3544

.github/workflows/docs.yaml

@@ -51,17 +51,3 @@ jobs:
       run: postgrest-docs-spellcheck
     - name: Run dictcheck
       run: postgrest-docs-dictcheck
-
-
-  linkcheck:
-    name: Linkcheck
-    if: github.base_ref == 'main'
-    runs-on: ubuntu-22.04
-    steps:
-    - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
-    - name: Setup Nix Environment
-      uses: ./.github/actions/setup-nix
-      with:
-        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-        tools: docs.linkcheck.bin
-    - run: postgrest-docs-linkcheck

.github/workflows/linkcheck.yaml

@@ -0,0 +1,17 @@
+name: Linkcheck
+
+on:
+  schedule:
+    - cron: '1 2 * * 3'
+
+jobs:
+  linkcheck:
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+    - name: Setup Nix Environment
+      uses: ./.github/actions/setup-nix
+      with:
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+        tools: docs.linkcheck.bin
+    - run: postgrest-docs-linkcheck

docs/conf.py

@@ -295,13 +295,7 @@ def setup(app):
 # taken from https://github.com/sphinx-doc/sphinx/blob/82dad44e5bd3776ecb6fd8ded656bc8151d0e63d/sphinx/util/requests.py#L42
 user_agent = "Mozilla/5.0 (X11; Linux x86_64; rv:25.0) Gecko/20100101 Firefox/25.0"
 
-# TODO: these pages are returning 403 right now. Verify if they can be fixed by addressing the issue:
-# https://github.com/PostgREST/postgrest/issues/3544
-linkcheck_ignore = [
-    r"https://stackoverflow.com/",
-    r"https://www.patreon.com/postgrest",
-    r"https://blog.frankel.ch/poor-man-api",
-]
+linkcheck_ignore = []
 
 # sphinx-tabs configuration
 sphinx_tabs_disable_tab_closing = True