chore: replace dotenv with dotenvy (#2003)

* chore: replace `dotenv` with `dotenvy`

The former appears to be unmaintained and the latter is a drop-in replacement.

* chore: fix all warnings

examples/postgres/json/Cargo.toml

@@ -6,7 +6,7 @@ workspace = "../../../"
 
 [dependencies]
 anyhow = "1.0"
-dotenv = "0.15.0"
+dotenvy = "0.15.0"
 futures = "0.3"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"

examples/postgres/json/src/main.rs

@@ -33,7 +33,7 @@ struct Row {
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     let args = Args::from_args_safe()?;
-    let pool = PgPool::connect(&dotenv::var("DATABASE_URL")?).await?;
+    let pool = PgPool::connect(&dotenvy::var("DATABASE_URL")?).await?;
 
     match args.cmd {
         Some(Command::Add) => {