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/mockable-todos/Cargo.toml

@@ -10,6 +10,6 @@ futures = "0.3"
 sqlx = { path = "../../../", features = ["postgres", "offline", "runtime-tokio-native-tls"] }
 structopt = "0.3"
 tokio = { version = "1.20.0", features = ["macros"]}
-dotenv = "0.15.0"
+dotenvy = "0.15.0"
 async-trait = "0.1.41"
 mockall = "0.11"

examples/postgres/mockable-todos/src/main.rs

@@ -1,5 +1,4 @@
 use async_trait::async_trait;
-use dotenv;
 use sqlx::postgres::PgPool;
 use std::{env, io::Write, sync::Arc};
 use structopt::StructOpt;
@@ -18,7 +17,7 @@ enum Command {
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
-    dotenv::dotenv().ok();
+    dotenvy::dotenv().ok();
     let args = Args::from_args_safe()?;
     let pool = PgPool::connect(&env::var("DATABASE_URL")?).await?;
     let todo_repo = PostgresTodoRepo::new(pool);