extract: Avoid creating invalid ISO date strings

Fixes #175
7 jobs for sam/no-year-zero in 8 minutes and 46 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #1350372
test-fedora-latest

00:01:24

passed #1351157
test-fedora-rawhide

00:01:47

passed #1350146
test-ubuntu-rolling

00:03:12

failed #1350144
test-fedora-latest

00:03:20

failed #1350145
test-fedora-rawhide

00:04:15

failed #1350368
test-fedora-rawhide

00:07:51

 
  Analysis
passed #1350147
coverage-analysis

00:02:21

49.3%