chore(workflows): bump docgen-action (#534)

Context:
https://leanprover.zulipchat.com/#narrow/channel/423402-PrimeNumberTheorem.2B/topic/CI.20issues/near/570938802

---------

Co-authored-by: Michael Rothgang <rothgang@math.uni-bonn.de>

Author: pitmonticone

.github/workflows/push.yml

@@ -61,7 +61,7 @@ jobs:
             cp paper/main.pdf docs/paper.pdf
 
       - name: Compile blueprint and documentation
-        uses: leanprover-community/docgen-action@deed0cdc44dd8e5de07a300773eb751d33e32fc8 # 2025-10-26
+        uses: leanprover-community/docgen-action@3dbd3475a9bc8d22fd786a8f8efe1869457da7cc # 2026-01-15
         with:
           blueprint: true
           homepage: docs

.github/workflows/push_pr.yml

@@ -36,7 +36,7 @@ jobs:
         run: env LEAN_ABORT_ON_PANIC=1 ~/.elan/bin/lake exe runLinter Carleson
 
       - name: Compile blueprint and documentation
-        uses: leanprover-community/docgen-action@deed0cdc44dd8e5de07a300773eb751d33e32fc8 # 2025-10-26
+        uses: leanprover-community/docgen-action@3dbd3475a9bc8d22fd786a8f8efe1869457da7cc # 2026-01-15
         with:
           blueprint: true
           homepage: docs