Using Bazel's manual disk cache GC CLI

[vibbix]

Does anyone know how to invoke Bazel's Diskcache GC from it's tool? There's no documentation on how to run it.

[meisterT]

cc @tjgq

[tjgq]

$ bazel build //src/tools/diskcache:gc
$ bazel-bin/src/tools/diskcache/gc \
    --disk_cache=/path/to/disk/cache \
    --max_age=7d \
    --max_size=2G

I'll add a usage example to the README.