Revert ":100: change to using calendar versions"

This reverts commit 024990f.

README.md

@@ -106,10 +106,6 @@ yarn add us-zips
 npm install us-zips
 ```
 
-:information_source: **NOTE:** Due to ZIP codes always changing, this package
-uses calendar versioning (aka [CalVer][5]). This means each year will have a
-separate "major" version from npm and Yarn's perspective.
-
 ## Acknowledgments
 
 Data for ZIP codes and their geolocations was generated from [this file][1],
@@ -131,4 +127,3 @@ MIT
 [2]: https://github.com/blakek/geo2zip
 [3]: https://github.com/blakek/standardize-geolocation
 [4]: https://www.census.gov/geographies/reference-files/time-series/geo/gazetteer-files.html
-[5]: https://calver.org/

package.json

@@ -1,6 +1,6 @@
 {
   "name": "us-zips",
-  "version": "2021.11.0",
+  "version": "5.1.0",
   "description": "A list of US ZIP codes and their geolocations",
   "main": "index.js",
   "repository": {