Set Cache-Control headers for certain content on Firebase

My reasoning is:

* any CSS or JS files
	their name contains their hash — 1 month
* anything under img folder
	might change while keeping name — 1 day
* any image anywhere except img folder
	usually giant photos attached to blog posts, rarely change and if they do, they usually change name as well — 1 month

firebase.json

@@ -5,6 +5,35 @@
       "firebase.json",
       "**/.*",
       "**/node_modules/**"
+    ],
+    "headers": [
+      {
+        "source": "@(js|css)/*.@(js|css)",
+        "headers": [
+          {
+            "key": "Cache-Control",
+            "value": "max-age=2628000"
+          }
+        ]
+      },
+      {
+        "source": "img/**",
+        "headers": [
+          {
+            "key": "Cache-Control",
+            "value": "max-age=86400"
+          }
+        ]
+      },
+      {
+        "source": "!(img)/**/*.@(jpg|jpeg|png|webp)",
+        "headers": [
+          {
+            "key": "Cache-Control",
+            "value": "max-age=2628000"
+          }
+        ]
+      }
     ]
   }
 }