ci: adopt reusable workflows from `named-data/actions`

Change-Id: I372cc2fa1b26cede28982bbd88ca445eb08eef5c
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 9b1f305..48851ba 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -1,33 +1,10 @@
 name: Docs
 on:
   push:
-    paths-ignore:
-      - '*.md'
-      - '.mailmap'
   workflow_dispatch:
 
-permissions:
-  contents: read
+permissions: {}
 
 jobs:
-  build:
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [macos-latest, ubuntu-latest]
-    env:
-      JOB_NAME: Docs
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Install dependencies
-        run: |
-          find .jenkins.d/ -type f -name '[1-9]*.sh' -exec chmod -x '{}' +
-          ./.jenkins
-      - name: Build documentation
-        run: |
-          pybindir=$(python3 -c 'import sysconfig; print(sysconfig.get_path("scripts", "posix_user"))')
-          export PATH="${pybindir}${PATH:+:}${PATH}"
-          ./waf --color=yes configure
-          ./waf --color=yes build --targets=manpages
+  man:
+    uses: named-data/actions/.github/workflows/docs-man.yml@v1