deploy: manually enforce HTTPS links in book/ and docs/

The new checks for HTTPS enforcement found a couple of problems:
git#1953 (comment)

Essentially, some (quite stale) translations of the ProGit book, as well
as manual pages of older Git versions, use http://git-scm.com links. And
those are basically outside of our control to fix properly (in
particular the manual pages of older Git versions).

So let's just work around this by manually replacing them.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/actions/deploy-to-github-pages/action.yml

@@ -74,6 +74,13 @@ runs:
       shell: bash
       run: hugo config && hugo --baseURL "${{ env.base_url }}/"
 
+    - name: enforce HTTPS in links to git-scm.com from external sources (book, docs, ...)
+      if: startsWith(env.base_url, 'https://')
+      shell: bash
+      run: |
+        find public/book public/docs -name \*.html -print0 |
+        xargs -0r sed -i 's,http://git-scm\.com,https://git-scm.com,g'
+
     - name: run Pagefind ${{ env.PAGEFIND_VERSION }} to build the search index
       shell: bash
       run: npx -y pagefind@${{ env.PAGEFIND_VERSION }} --site public