chore(deps): let only the site-build group bump the site pins

requirements-dev.txt includes scripts/site/requirements.txt with -r, so the
root pip entry and the /scripts/site entry both proposed the same Jinja2 and
MarkupSafe bump (#480 and #481 are byte-identical). The root entry now
ignores those two; the site-build group keeps owning them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

Author: TMHSDigital

.github/dependabot.yml

@@ -29,6 +29,12 @@ updates:
     target-branch: "main"
     commit-message:
       prefix: "chore(deps)"
+    # requirements-dev.txt pulls in scripts/site/requirements.txt with -r, so
+    # without this the site pins get two identical PRs (site-build and
+    # dev-tools) on every bump. The /scripts/site entry owns them.
+    ignore:
+      - dependency-name: "jinja2"
+      - dependency-name: "markupsafe"
     groups:
       dev-tools:
         patterns: