chore: Adjusting dates for updated countries in Readme

Author: KristjanESPERANTO

README.md

@@ -4,17 +4,17 @@ This repo aggregates and stores freely accessible calendar data on the following
 
 + Albania (public holidays and school holidays from 2020)
 + Andorra (public holidays and school holidays from 2020)
-+ Austria (public holidays and school holidays from 2020)
++ Austria (public holidays and school holidays from 2017)
 + Belarus (public holidays and school holidays from 2020)
 + Belgium (public holidays and school holidays from 2020)
 + Brazil (public holidays from 2020)
 + Bulgaria (public holidays and school holidays from 2020)
 + Croatia (public holidays and school holidays from 2020)
 + Czechia (public holidays and school holidays from 2020)
 + Estonia (public holidays and school holidays from 2020)
-+ France (public holidays and school holidays from 2020)
-+ Germany (public holidays and school holidays from 2020)
-+ Hungary (public holidays and school holidays from 2020)
++ France (public holidays and school holidays from 2018)
++ Germany (public holidays and school holidays from 2012)
++ Hungary (public holidays and school holidays from 2015)
 + Ireland (public holidays and school holidays from 2020)
 + Italy (public holidays and school holidays from 2020, Initial data from [@48DESIGN](https://github.com/48design))
 + Latvia (public holidays and school holidays from 2020)
@@ -28,7 +28,7 @@ This repo aggregates and stores freely accessible calendar data on the following
 + Netherlands (public holidays and school holidays from 2020)
 + Poland (public holidays and school holidays from 2020)
 + Portugal (national and district public holidays from 2020, Initial data from [@48DESIGN](https://github.com/48design))
-+ Romania (public holidays and school holidays from 2020)
++ Romania (public holidays and school holidays from 2015)
 + San Marino (public holidays and school holidays from 2020)
 + Serbia (public holidays and school holidays from 2020)
 + Slovakia (public holidays and school holidays from 2020)