update to pam 0.7 (renamed from pam-auth)

It now supports custom conversation methods, so instead of
new() we ask for a default authenticator taking a password
via with_password(). Since the password is now handled by
the now separate conversation handler, `set_credentials()`
is now called on the handler we get via `.get_handler()`.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

Cargo.toml

@@ -38,4 +38,4 @@ walkdir = "2"
 md5 = "0.6"
 base64 = "0.10"
 pam-sys = "0.5"
-pam-auth = "0.5"
+pam = "0.7"