Merge pull request #116 from adolgert/docs/build-on-version

this change to CI should build docs when I make a new tagged version

Author: adolgert

.github/workflows/ci.yml

@@ -1,7 +1,11 @@
 name: CI
 on:
-  - push
-  - pull_request
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*'
+  pull_request:
 jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}