* vecgeom: require exact version of veccore
Fixes configure error from downstream package:
```
CMake Error at /rnsdhpc/code/spack/opt/spack/apple-clang/cmake/7zgbrwt/share/cmake-3.22/Modules/CMakeFindDependencyMacro.cmake:47 (find_package):
Could not find a configuration file for package "VecCore" that is
compatible with requested version "0.8.0".
The following configuration files were considered but not accepted:
/rnsdhpc/code/spack/var/spack/environments/celeritas/.spack-env/view/lib/cmake/VecCore/VecCoreConfig.cmake, version: 0.6.0
```
* veccore: add new versions
9ac207c901