bump proxmox-async dep to 0.4

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

pbs-tools/Cargo.toml

@@ -33,7 +33,7 @@ walkdir = "2"
 zstd = { version = "0.6", features = [ "bindgen" ] }
 
 #proxmox = { version = "0.15.3", default-features = false, features = [ "tokio" ] }
-proxmox-async = "0.3"
+proxmox-async = "0.4"
 proxmox-borrow = "1"
 proxmox-io = { version = "1", features = [ "tokio" ] }
 proxmox-lang = { version = "1.1" }