mark non upgrable iced

Cargo.toml

@@ -13,6 +13,7 @@ keywords = ["guitar", "tablature", "music"]
 [dependencies]
 nom = "7.1.3"
 encoding_rs = "0.8.34"
+# Can't upgrade to 0.13.0 as it bumps the MSRV to 1.80 which breaks the Win7&8 builds :s
 iced = { version = "0.13.0", features = ["advanced", "canvas", "tokio", "debug"] }
 iced_aw = { version = "0.10.0", default-features = false, features = ["wrap"] }
 tokio = { version = "1.40.0", features = ["fs", "sync"] }