* Helix/pico use post_rules.mk insted of local_features.mk
Tested with the following procedure.
```
git checkout 77a93fec79 (qmk/develop)
make clean
make helix/pico:all:check-md5
make helix/pico/sc:all:check-md5
git checkout helix_use_post_rules.mk
make clean
make helix/pico:all:check-md5
make helix/pico/sc:all:check-md5
```
* Helix/rev2 use post_rules.mk
Tested with the following procedure.
```
git checkout 77a93fec79 (qmk/develop)
make clean
make helix/pico:all:check-md5
make helix/pico/sc:all:check-md5
make helix/rev2:all:check-md5
make helix/rev2/sc:all:check-md5
git checkout helix_use_post_rules.mk
make clean
make helix/pico:all:check-md5
make helix/pico/sc:all:check-md5
make helix/rev2:all:check-md5
make helix/rev2/sc:all:check-md5
```
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