Update SXG Origin Trial Token on HTTP Gateway

[lidel]

This is continuation of #453 and ipfs/in-web-browsers#121

I renewed our participation until Jan 25, 2019, but we need to update Origin-Trial header to new value:

Apz+MZlH/rQM6+d3sDPQYouRZMaRgp9YyhKhp3Gz527Zi3rCyt+vgNoPgfNkMTp408APUc+fxEAs5+MB7WgoHA4AAABeeyJvcmlnaW4iOiJodHRwczovL2lwZnMuaW86NDQzIiwiZmVhdHVyZSI6IlNpZ25lZEhUVFBFeGNoYW5nZU9yaWdpblRyaWFsIiwiZXhwaXJ5IjoxNTQ4NDIzNDA0fQ==

Note: this is time-sensitive (cc @kyledrake), as the old one will expire in one week:

Thanks for your participation in the origin trial for Signed HTTP Exchange! As a reminder, we previously issued a token as follows:
Origin: https://ipfs.io
Issued: 2018-11-08
Expires: 2018-12-20

You’ll need to renew your registration in order to continue using the feature on your site. If you do not renew, your site will lose access to the feature on 2018-12-20. Upon renewal, we’ll generate a new token to replace the expiring token on your site.

References

• [Meta] Signed HTTP Exchanges and WebPackage
• Signed HTTP Exchanges: Chrome Origin Trials (living document)
• Origin Trial Token Validator (to ensure token is correct and did not expire yet)

[kyledrake]

Done, thanks!