Use eleventyImport to control rebuilds of tag, blog, and feed pages

src/blog/tag.html

@@ -14,6 +14,9 @@
             "atom": "{{ page.url }}atom.xml",
             "json": "{{ page.url }}feed.json"
         }
+    },
+    "eleventyImport": {
+        "collections": ["tags", "posts"]
     }
 }
 ---