Mount /mnt/dockercache to docker image (#1191)

### Ticket
N/A

### Problem description
Mount /mnt/dockercache to docker image.
 - /mnt/dockercache:/mnt/dockercache
This was removed by accident in refactor
41464a8 [CI] reorganize workflows to
use python wheel (#1160)

### What's changed
Add mount /mnt/dockercache to docker image.
 - /mnt/dockercache:/mnt/dockercache

### Checklist
- [ x] New/Existing tests provide coverage for changes

.github/workflows/test.yml

@@ -55,6 +55,8 @@ jobs:
         - /etc/udev/rules.d:/etc/udev/rules.d
         - /lib/modules:/lib/modules
         - /opt/tt_metal_infra/provisioning/provisioning_env:/opt/tt_metal_infra/provisioning/provisioning_env
+        - /mnt/dockercache:/mnt/dockercache
+
     steps:
 
     - name: Fetch job id