improvement: added rollup visualizer.

Also made committing stats files part of release so the
files are always committed when a new version is published.

Also upgraded dependencies.

.gitignore

@@ -51,3 +51,4 @@ Gemfile.lock
 
 # Rollup
 .rpt2_cache
+stats.html

.size-snapshot.json

@@ -1,20 +1,20 @@
 {
   "dist/index.js": {
-    "bundled": 167639,
-    "minified": 79706,
-    "gzipped": 21578
+    "bundled": 175096,
+    "minified": 83771,
+    "gzipped": 22386
   },
   "dist/index.es.js": {
-    "bundled": 161686,
-    "minified": 73935,
-    "gzipped": 21251,
+    "bundled": 168546,
+    "minified": 77418,
+    "gzipped": 22033,
     "treeshaked": {
       "rollup": {
-        "code": 53690,
-        "import_statements": 1227
+        "code": 56584,
+        "import_statements": 1270
       },
       "webpack": {
-        "code": 56665
+        "code": 59875
       }
     }
   }