Rework some details (env var, cargo desc)

Cargo.toml

@@ -4,7 +4,7 @@ version = "0.2.0"
 authors = ["Alex Auvolat <alex@adnab.me>", "Quentin Dufour <quentin@dufour.io>"]
 edition = "2021"
 license = "EUPL-1.2"
-description = "Encrypted mail storage over Garage"
+description = "A robust email server"
 
 [dependencies]
 # async runtime

src/main.rs

@@ -33,7 +33,7 @@ struct Args {
     #[clap(long)]
     dev: bool,
 
-    #[clap(short, long, env = "CONFIG_FILE", default_value = "aerogramme.toml")]
+    #[clap(short, long, env = "AEROGRAMME_CONFIG", default_value = "aerogramme.toml")]
     /// Path to the main Aerogramme configuration file
     config_file: PathBuf,
 }