fix: clap cannot downcast CLI flags to PathBuf

After the recent changes clap is not able to cast the CLI flags into
PathBuf type. To fix that, we can configure the value parser when the
Arg is created.

Signed-off-by: José Guilherme Vanz <jguilhermevanz@suse.com>

Author: jvanz

src/cli.rs

@@ -85,19 +85,22 @@ pub(crate) fn build_cli() -> Command {
             .long("cert-file")
             .value_name("CERT_FILE")
             .env("KUBEWARDEN_CERT_FILE")
+            .value_parser(clap::builder::PathBufValueParser::new())
             .help("Path to an X.509 certificate file for HTTPS"),
 
         Arg::new("key-file")
             .long("key-file")
             .value_name("KEY_FILE")
             .env("KUBEWARDEN_KEY_FILE")
+            .value_parser(clap::builder::PathBufValueParser::new())
             .help("Path to an X.509 private key file for HTTPS"),
 
         Arg::new("client-ca-file")
             .long("client-ca-file")
             .value_delimiter(',')
             .value_name("CLIENT_CA_FILE")
             .env("KUBEWARDEN_CLIENT_CA_FILE")
+            .value_parser(clap::builder::PathBufValueParser::new())
             .help("Path to an CA certificate file that issued the client certificate. Required to enable mTLS"),
 
         Arg::new("policies")