Build docs on tag push.

.github/workflows/docs.yml

@@ -0,0 +1,20 @@
+name: docs
+on:
+  push:
+    tags:
+      - 'v*'
+jobs:
+  deploy-docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: init
+        run: sudo apt update -yqq && sudo apt install doxygen
+      - name: clone docs repo
+        run: git clone https://github.com/karnkaul/bave-docs docs
+      - name: build docs
+        run: mkdir -p out/docs; doxygen Doxyfile
+      - name: create commit
+        run: cd out/docs; git add .; git commit -m "[Automated] Build docs."
+      - name: deploy docs
+        run: git push