update to proxmox-sys 0.2 crate

- imported pbs-api-types/src/common_regex.rs from old proxmox crate
- use hex crate to generate/parse hex digest
- remove all reference to proxmox crate (use proxmox-sys and
  proxmox-serde instead)

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

src/bin/proxmox_backup_manager/acme.rs

@@ -3,7 +3,7 @@ use std::io::Write;
 use anyhow::{bail, Error};
 use serde_json::Value;
 
-use proxmox::tools::fs::file_get_contents;
+use proxmox_sys::fs::file_get_contents;
 use proxmox_router::{cli::*, ApiHandler, RpcEnvironment};
 use proxmox_schema::api;