Move meeting two hours later, pin to GMT/UTC

Many of the test writing folks live in New Zealand and the meeting moves two
hours earlier in Southern Hemispherical Winter when pinned to PDT.

Author: hh

sigs.yaml

@@ -274,10 +274,10 @@ sigs:
     url: https://zoom.us/j/159990793
     archive_url: https://docs.google.com/document/d/1HtTI0rJEGP_MSf6eO87aCmx_tzpovPAAg7U2Zxwm8FE/edit#
     recordings_url: https://www.youtube.com/playlist?list=PL69nYSiGNLP03VEluzh0wpSRPzgve8kI5
-  - description: conformance Office Hours
+  - description: Conformance Office Hours
     day: Tuesday
-    time: "12:00"
-    tz: PT (Pacific Time)
+    time: "19:00"
+    tz: UTC
     frequency: weekly
     url: https://zoom.us/j/427337923
     archive_url: https://docs.google.com/document/d/1W31nXh9RYAb_VaYkwuPLd1hFxuRX3iU0DmaQ4lkCsX8/edit#