proc: process info files should be locked during writing

[pmrowla]

In certain situations it's possible that a reader tries to load proc info from file while it's being written to which causes a jsondecodeerror. ProcessManager should provide minimal amount of synchronization for these cases.

Alternatively, at a minimum we should just write to temporary paths (i.e. output_path.json.<random suffix>) and then fs.move to replace the existing file in:

dvc-task/src/dvc_task/proc/process.py

Lines 133 to 138 in d132caa

	def _dump(self):
	self._make_wdir()
	with open(self.info_path, "w", encoding="utf-8") as fobj:
	json.dump(self.info.asdict(), fobj)
	with open(self.pidfile_path, "w", encoding="utf-8") as fobj:
	fobj.write(str(self.pid))