Add ORACLE_USERID_2 to github actions

[djzort]

For testing reauth there needs to be an additional user in the ORACLE_USERID_2 environment variable. See it in the example Dockerfile here https://github.com/perl5-dbi/DBD-Oracle/blob/master/maint/Dockerfile#L22 and here https://github.com/perl5-dbi/DBD-Oracle/blob/master/maint/scripts/01_install_oracle_xe.bash#L52

The oracle container has a method to add users 2+ as documented here https://hub.docker.com/r/gvenzl/oracle-free#database-users

It would be nice for someone to work out how to make these work with github actions. Then we get that extra test running each time.