(#2364) Set env variable when using official build
(#2364) Set env variable when using official build

When running the official build of Chocolatey within the contianer, we
also want to switch the strong name key that is used as part of the
build.

This is done by setting the CHOCOLATEY_OFFICIAL_KEY environment variable
to the location that this file can be found.

jberezanski/choco,TheBigBear/choco,jberezanski/choco,TheBigBear/choco,TheBigBear/choco,jberezanski/choco