Updated link in readme leading to Decode Timestamp doc at w3.org

[tobysoby]

Description

Heya, fixed a link in the Readme. Had to open this a couple of times in the last two days and it bothered me...
btw: Thanks for the nice Documentation with all the links! :-)

Specific Changes proposed

fixed a link in the Readme

Requirements Checklist

• [/] Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

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