Some lastUpdated entries have an unexpected "+" added to the date

[foster33]

This issue was initially brought up in #31

There seems to be an issue where some of the lastUpdated dates are incorrect. They include a "+" in front of them.

Example (see NAME_TOKEN & NETWORK_NAME_TOKEN):

[foster33]

It seems as though those fields (and others) are having issues since their lastUpdated timestamps are from 1952 (pre 1970). Looks like commit 7ca55b changed the logic of how timestamps are converted to be displayed on the data dictionary page and might have broken this.