TypeIds.h : Added range for AtomsGaffer

[ivanimanishi]

AtomsGaffer is currently claiming a range that has now been taken over by Gaffer 1.6.

https://github.com/Toolchefs/atomsGaffer/blob/master/include/AtomsGaffer/TypeIds.h

In the file you can see a note about updating cortex to claim the range in question, but that was never done.

I believe the solution is to change AtomsGaffer's range, and claim that new range here, so we don't run the risk of the same happening again in the future.

I'll update AtomsGaffer once the Cortex PR is approved.

• I have read the contribution guidelines.
• I have updated the documentation, if applicable.
• I have tested my change(s) in the test suite, and added new test cases where necessary.
• My code follows the Cortex project's prevailing coding style and conventions.

[danieldresser-ie]

Looks fine to me. I've added @johnhaddon as a reviewer in case he has any other opinions on how to allocate ranges, but this should be fine.

[ivanimanishi]

Ended up merging it to RB-10.6 to simplify the process, given that typeIds change very rarely, and we just need to make sure nobody tries to use the reserved range for something else.