Pinning not ignored

When I do
```yaml
build:
ignore_run_exports:
- hdf5

requirements:
host:
- hdf5 *
run:
- hdf5 *
```
the bot fails to ignore the pinning of HDF5 (ref: https://github.com/conda-forge/highfive-feedstock/pull/24).

Instead the bot correctly ignores pinning of HDF5 when I do:
```yaml
build:
ignore_run_exports_from:
- hdf5 *

requirements:
host:
- hdf5 *
run:
- hdf5 *
```
(ref: https://github.com/conda-forge/highfive-feedstock/pull/25)

> A personal note: in both cases I find the required syntax quite verbose. I would like to use only `hdf5 *` in requirements or `hdf5` in `ignore_run_expots`.