Update dependency firebase to v12 (#324)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -23,7 +23,7 @@
     "animate.css": "3.1.1",
     "animejs": "3.2.1",
     "disqusjs": "3.1.0",
-    "firebase": "11.9.1",
+    "firebase": "12.0.0",
     "gitalk": "1.8.0",
     "hexo-generator-searchdb": "1.5.0",
     "katex": "0.16.9",