Cannot run as non-root

```
python3 # as user, not root
import solcx
solcx.get_solcx_install_folder()
PosixPath('/home/admin/.solcx')

```
solcx.install_solc(version="0.4.26", show_progress=True, solcx_binary_path=None)

```
File "/home/admin/.local/share/virtualenvs/terd-H6HPKpgI/lib/python3.7/site-packages/solcx/install.py", line 433, in install_solc
process_lock = get_process_lock(str(version))
File "/home/admin/.local/share/virtualenvs/terd-H6HPKpgI/lib/python3.7/site-packages/solcx/utils/lock.py", line 28, in get_process_lock
_locks[lock_id] = UnixLock(lock_id)
File "/home/admin/.local/share/virtualenvs/terd-H6HPKpgI/lib/python3.7/site-packages/solcx/utils/lock.py", line 40, in __init__
self._lock_file = self._lock_path.open("w")
File "/usr/lib/python3.7/pathlib.py", line 1186, in open
opener=self._opener)
File "/usr/lib/python3.7/pathlib.py", line 1039, in _opener
return self._accessor.open(self, flags, mode)

PermissionError: [Errno 13] Permission denied: '/tmp/.solcx-lock-0.4.26'
```
solcx should restrict itself to /home/admin/.solcx folder

### Environment information
py-solc==3.2.0
py-solc-x==1.1.1
Python 3.7.3
Debian 10