Update flake and deps, continue implementing basic structure

src/sources/github.rs

@@ -0,0 +1,11 @@
+pub struct KagamiSourceGithub {
+  host: String,
+}
+
+impl KagamiSourceGithub {
+  pub fn new(host: &str) -> Self {
+    Self {
+      host: host.to_string(),
+    }
+  }
+}