Drop once_cell dependency

The bump of msrv to 1.70 is okay, as we will be updating soon to
zbus 4 (once released) which requires 1.75

Cargo.toml

@@ -9,7 +9,7 @@ license = "MIT"
 name = "ashpd"
 repository = "https://github.com/bilelmoussaoui/ashpd"
 version = "0.7.0"
-rust-version = "1.65"
+rust-version = "1.70"
 
 [features]
 async-std = ["zbus/async-io", "dep:async-fs", "dep:async-net"]
@@ -32,7 +32,6 @@ gdk4wayland = { git = "https://github.com/gtk-rs/gtk4-rs", package = "gdk4-wayla
 gdk4x11 = { git = "https://github.com/gtk-rs/gtk4-rs", package = "gdk4-x11", version = "0.8", optional = true }
 gtk4 = { git = "https://github.com/gtk-rs/gtk4-rs", version = "0.8", optional = true }
 libc = { version = "0.2", optional = true }
-once_cell = "1.14"
 pw = { package = "pipewire", version = "0.7", optional = true }
 rand = { version = "0.8", default-features = false }
 raw-window-handle = { version = "0.6", optional = true }

src/lib.rs

@@ -12,7 +12,7 @@ compile_error!("You can't enable both async-std & tokio features at once");
 /// Alias for a [`Result`] with the error type `ashpd::Error`.
 pub type Result<T> = std::result::Result<T, Error>;
 
-static IS_SANDBOXED: OnceCell<bool> = OnceCell::new();
+static IS_SANDBOXED: OnceLock<bool> = OnceLock::new();
 
 /// Interact with the user's desktop such as taking a screenshot, setting a
 /// background or querying the user's location.
@@ -34,8 +34,9 @@ mod proxy;
 /// received an update & install it.
 pub mod flatpak;
 mod helpers;
+use std::sync::OnceLock;
+
 pub use enumflags2;
-use once_cell::sync::OnceCell;
 pub use url;
 pub use zbus::{self, zvariant};
 

src/proxy.rs

@@ -1,7 +1,6 @@
-use std::{fmt::Debug, future::ready, ops::Deref};
+use std::{fmt::Debug, future::ready, ops::Deref, sync::OnceLock};
 
 use futures_util::{Stream, StreamExt};
-use once_cell::sync::OnceCell;
 use serde::{Deserialize, Serialize};
 use zbus::zvariant::{ObjectPath, OwnedValue, Type};
 #[cfg(feature = "tracing")]
@@ -24,7 +23,7 @@ pub(crate) const FLATPAK_PATH: &str = "/org/freedesktop/portal/Flatpak";
 pub(crate) const FLATPAK_DEVELOPMENT_DESTINATION: &str = "org.freedesktop.Flatpak";
 pub(crate) const FLATPAK_DEVELOPMENT_PATH: &str = "/org/freedesktop/Flatpak/Development";
 
-static SESSION: OnceCell<zbus::Connection> = OnceCell::new();
+static SESSION: OnceLock<zbus::Connection> = OnceLock::new();
 
 #[derive(Debug)]
 pub struct Proxy<'a> {