Releases can now be created... sorta

The API token is read from the environment variable `RELEASE_KEY_GITEA`.
"GITEA" is on the end because Gitea itself will refuse to allow users to
configure Act variables starting with the name "GITEA_".

All information about the release is hard-coded right now. I just needed
to see it hit the API and appear on the Gitea page. Hooking up the extra
options is up next.

src/cli.rs

@@ -15,4 +15,8 @@ pub struct Args {
 #[derive(Subcommand, Debug)]
 pub enum Commands {
     ListReleases,
+    CreateRelease {
+        #[arg()]
+        name: String,
+    },
 }