Update to rustls-pemfile alpha

Cargo.toml

@@ -20,7 +20,7 @@ percent-encoding = "2.3"
 rcgen = "0.11.1"
 reqwest = { version = "0.11", features = ["rustls-tls-manual-roots"] }
 ring = "0.17.0"
-rustls-pemfile = "1"
+rustls-pemfile = "2.0.0-alpha.1"
 serde = { version = "1.0.183", features = ["derive"] }
 tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
 webpki = { package = "rustls-webpki", version = "=0.102.0-alpha.6" }

tests/codegen.rs

@@ -308,15 +308,11 @@ impl CertificateMetadata {
 
     /// Returns the DER encoding of the certificate contained in the metadata PEM. Panics if
     /// there is an error, or no certificate in the PEM content.
-    fn der(&self) -> Vec<u8> {
-        let certs = rustls_pemfile::certs(&mut self.pem().as_bytes()).expect("invalid PEM");
-        if certs.len() > 1 {
-            panic!("more than one certificate in metadata PEM");
-        }
-        certs
-            .first()
-            .expect("missing certificate in metadata PEM")
-            .clone()
+    fn der(&self) -> CertificateDer<'static> {
+        rustls_pemfile::certs(&mut self.pem().as_bytes())
+            .next()
+            .unwrap()
+            .expect("invalid PEM")
     }
 
     /// Returns the serial number for the certificate. Panics if the certificate serial number